diff --git a/include/operators/G2BMM.h b/include/operators/G2BMM.h
index a17a785f..52f2a2c8 100644
--- a/include/operators/G2BMM.h
+++ b/include/operators/G2BMM.h
@@ -2,7 +2,11 @@
 #include "core/operator.h"
 #include <assert.h>
 namespace infini {
-
+/**
+ * @brief General to band matrix multiplication, which is used for Longformer
+ * model. See https://arxiv.org/pdf/2004.05150.pdf for detail.
+ *
+ */
 class G2BMMObj : public OperatorObj {
   private:
     // to be implemented
@@ -13,15 +17,17 @@ class G2BMMObj : public OperatorObj {
 
   public:
     /**
-     * @brief This comments show how operators is defined in InfiniTensor. The
-     * constructor can create output tensors for the operator or not, which
-     * depends on `graph`.
+     * @brief Construct a new G2BMM object.
      *
-     * @param graph If graph is not empty, create outputs in the constructor.
-     * Otherwise, check the provided shape with the results of `inferShape` in
-     * `checkValid`.
+     * @param graph The computation graph that this operator belongs to.
+     * @param A The input tensor.
+     * @param B The input tensor.
      * @param C C is the output of G2BMM. If outputs are going to be created in
      * the constructor, C should be an empty Ref.
+     * @param width The width of the attention window.
+     * @param dilation The dilation of the attention window.
+     * @param bias The bias tensor.
+     * @param act The activation.
      */
     G2BMMObj(GraphObj *graph, Tensor A, Tensor B, Tensor C, const int width,
              const int dilation, Tensor bias = nullptr,
diff --git a/include/operators/GBMM.h b/include/operators/GBMM.h
index 757f1486..ebfed659 100644
--- a/include/operators/GBMM.h
+++ b/include/operators/GBMM.h
@@ -2,7 +2,12 @@
 #include "core/operator.h"
 #include <assert.h>
 namespace infini {
-
+/**
+ * @brief General band matrix multiplication. See
+ * https://cscproxy.mpi-magdeburg.mpg.de/mpcsc/benner/pub/brdeq-cle2014.pdf for
+ * detail.
+ *
+ */
 class GBMMObj : public OperatorObj {
   private:
     int dilation;
@@ -12,15 +17,16 @@ class GBMMObj : public OperatorObj {
 
   public:
     /**
-     * @brief This comments show how operators is defined in InfiniTensor. The
-     * constructor can create output tensors for the operator or not, which
-     * depends on `graph`.
+     * @brief Construct a new GBMM object.
      *
-     * @param graph If graph is not empty, create outputs in the constructor.
-     * Otherwise, check the provided shape with the results of `inferShape` in
-     * `checkValid`.
-     * @param C C is the output of GBMM. If outputs are going to be created in
+     * @param graph The computation graph that this operator belongs to.
+     * @param A The input tensor.
+     * @param B The input tensor.
+     * @param C C is the output of G2BMM. If outputs are going to be created in
      * the constructor, C should be an empty Ref.
+     * @param dilation The dilation of the attention window.
+     * @param bias The bias tensor.
+     * @param act The activation.
      */
     GBMMObj(GraphObj *graph, Tensor A, Tensor B, Tensor C, const int dilation,
             Tensor bias = nullptr, ActType act = ActType::None);
diff --git a/include/operators/batch_norm.h b/include/operators/batch_norm.h
index c2c0ad54..20842615 100644
--- a/include/operators/batch_norm.h
+++ b/include/operators/batch_norm.h
@@ -2,11 +2,34 @@
 #include "core/operator.h"
 
 namespace infini {
+/**
+ * @brief See https://arxiv.org/abs/1502.03167 for the detail of batch
+ * normalization.
+ *
+ */
 class BatchNormObj : public OperatorObj {
     float momentum, eps;
     bool training;
 
   public:
+    /**
+     * @brief Construct a new BatchNorm object.
+     *
+     * @param graph The computation graph that this operator belongs to.
+     * @param input The input tensor of BatchNorm. For image data, the input
+     * shape is usually [N, C, H, W].
+     * @param output The output tensor of BatchNorm, which should have the same
+     * shape as the input tensor.
+     * @param mean The mean tensor, which has a shape of [C].
+     * @param var The var tensor, which has a shape of [C].
+     * @param scale The scale tensor, which has a shape of [C].
+     * @param bias The bias tensor, which has a shape of [C].
+     * @param momentum Factor used in computing the running mean and variance.
+     * Default is 0.9.
+     * @param eps The epsilon value to use to avoid division by zero. Default is
+     * 1e-5.
+     * @param training Set to true when used for training.
+     */
     BatchNormObj(GraphObj *graph, Tensor input, Tensor output, Tensor mean,
                  Tensor var, Tensor scale, Tensor bias, float momentum = 0.9,
                  float eps = 1e-5, bool training = false);
diff --git a/include/operators/concat.h b/include/operators/concat.h
index af5e9790..c3d9c4f3 100644
--- a/include/operators/concat.h
+++ b/include/operators/concat.h
@@ -2,10 +2,23 @@
 #include "core/operator.h"
 
 namespace infini {
+/**
+ * @brief Concatenate several tensors into one. All the input tensors should
+ * have the same shape except for the concatenated dimension.
+ *
+ */
 class ConcatObj : public OperatorObj {
     int dim;
 
   public:
+    /**
+     * @brief Construct a new Concat object.
+     *
+     * @param graph The computation graph that this operator belongs to.
+     * @param inputs The input tensors to be concatenated.
+     * @param output Concatenated tensor.
+     * @param dim The dimension to concatenate on.
+     */
     ConcatObj(GraphObj *graph, TensorVec inputs, Tensor output, int dim);
     OP_CLONE(ConcatObj);
 
diff --git a/include/operators/conv.h b/include/operators/conv.h
index df27e8c1..e2ed1372 100644
--- a/include/operators/conv.h
+++ b/include/operators/conv.h
@@ -2,7 +2,30 @@
 #include "core/operator.h"
 
 namespace infini {
-
+/**
+ * @brief Convolution. Currently this operator only supports 2-D convolution.
+ * This is the base class for convolution and transposed convolution.
+ * The input tensor has four dimensions, called N (batch), C (channel), H
+ * (height), and W (width) respectively; The weight tensor has four dimensions,
+ * called F (number of filters), C (channel), R (height of weight), and S (width
+ * of weight) respectively; The output tensor has four dimensions, called N, F,
+ * H, and W respectively. By default, we take NCHW layout for the input and
+ * output tensors, and FCRS layout for the weight tensor.
+ * Convolutions have three attributes, called padding, stride, and dilation.
+ * Padding is assigned by padding mode or padding size. Padding mode must be
+ * Other, Same, or Valid (see the definition of enum class PaddingMode). Same
+ * means the output has the same shape as the input. Valid means padding size is
+ * 0. Other means padding size is assigned by value ph and pw, denoting the
+ * padding size along height dimension and weight dimension, respectively.
+ * Stride is assigned by sh and sw, denoting the stride along height dimension
+ * and weight dimension, respectively.
+ * Dilation is assigned by dh and dw, denoting the dilation along height
+ * dimension and weight dimension, respectively.
+ * See
+ * https://towardsdatascience.com/types-of-convolutions-in-deep-learning-717013397f4d
+ * for a detailed explanation of convolution.
+ *
+ */
 class ConvBaseObj : public OperatorObj {
   public:
     // When PaddingMode is Other, ConvObj will use padding size (ph, pw)
@@ -18,7 +41,7 @@ class ConvBaseObj : public OperatorObj {
     int sh, sw;
     int dh, dw;
     PaddingMode padding;
-    // auxiliary attributes. Descripitions stand on a forward perspective,
+    // Auxiliary attributes. Descripitions stand on a forward perspective,
     // i.e., convTransposed2d is not regarded as the backward of conv2d.
     int n;    // batch size
     int c;    // input/output channel for conv2d/convTransposed2d
@@ -27,10 +50,43 @@ class ConvBaseObj : public OperatorObj {
     int r, s; // weight shape
 
   public:
-    // Constructors for explicitly setting padding size
+    /**
+     * @brief Construct a new ConvBase object by explicitly setting padding
+     * size.
+     *
+     * @param opType Indicate if this is a convolution or transposed
+     * convolution.
+     * @param inputs The input, weight and bias tensors. Bias is optional.
+     * FIXME: Split inputs into three parameters, input, weight, and bias.
+     * @param output The output tensor.
+     * @param ph Padding along height dimension.
+     * @param pw Padding along weight dimension.
+     * @param sh Stride along height dimension.
+     * @param sw Stride along weight dimension.
+     * @param dh Dilation along height dimension.
+     * @param dw Dilation along weight dimension.
+     * @param inputInConvFWD To be removed.
+     * @param weightInConvFWD To be removed.
+     */
     ConvBaseObj(OpType opType, TensorVec inputs, Tensor &output, int ph, int pw,
                 int sh, int sw, int dh, int dw, const Tensor &inputInConvFWD,
                 const Tensor &weightInConvFWD);
+    /**
+     * @brief Construct a new ConvBase object by setting padding mode.
+     *
+     * @param opType Indicate if this is a convolution or transposed
+     * convolution.
+     * @param inputs The input, weight and bias tensors. Bias is optional.
+     * FIXME: Split inputs into three parameters, input, weight, and bias.
+     * @param output The output tensor.
+     * @param mode Padding mode, which is set to Other, Same, or Valid.
+     * @param sh Stride along height dimension.
+     * @param sw Stride along weight dimension.
+     * @param dh Dilation along height dimension.
+     * @param dw Dilation along weight dimension.
+     * @param inputInConvFWD To be removed.
+     * @param weightInConvFWD To be removed.
+     */
     ConvBaseObj(OpType opType, TensorVec inputs, Tensor &output,
                 PaddingMode mode, int sh, int sw, int dh, int dw,
                 const Tensor &inputInConvFWD, const Tensor &weightInConvFWD);
diff --git a/include/operators/element_wise.h b/include/operators/element_wise.h
index 6f6b25c2..c3ffe9f1 100644
--- a/include/operators/element_wise.h
+++ b/include/operators/element_wise.h
@@ -2,8 +2,23 @@
 #include "core/operator.h"
 
 namespace infini {
+/**
+ * @brief Base class of **binary** element-wise operators.
+ * Unary operators like activations are not the derived classes of
+ * ElementWiseObj.
+ *
+ */
 class ElementWiseObj : public OperatorObj {
   public:
+    /**
+     * @brief Construct a new ElementWise object
+     *
+     * @param type Operator type.
+     * @param graph The computation graph that this operator belongs to.
+     * @param input0 The first input tensor.
+     * @param input1 The second input tensor.
+     * @param output The output tensor.
+     */
     ElementWiseObj(OpType type, GraphObj *graph, Tensor input0, Tensor input1,
                    Tensor output);
     optional<vector<Shape>> inferShape(const TensorVec &inputs) const override;
diff --git a/include/operators/extend.h b/include/operators/extend.h
index 905e388c..f749793f 100644
--- a/include/operators/extend.h
+++ b/include/operators/extend.h
@@ -2,10 +2,24 @@
 #include "core/operator.h"
 
 namespace infini {
+/**
+ * @brief Copy a tensor along a centain dimension for multiple times.
+ *
+ */
 class ExtendObj : public OperatorObj {
     int dim, num; // copy num times at the dim.
 
   public:
+    /**
+     * @brief Construct a new Extend object.
+     *
+     * @param graph The computation graph that this operator belongs to.
+     * @param input The input tensor.
+     * @param output The extened tensor.
+     * @param dim The dimension to extend on.
+     * @param num The number of times to copy when extending. The dimension size
+     * of `dim` becomes `num+1` times after extending.
+     */
     ExtendObj(GraphObj *graph, Tensor input, Tensor output, int dim,
               int num = 1);
     OP_CLONE(ExtendObj);
diff --git a/include/operators/gather.h b/include/operators/gather.h
index f8f33555..da86c502 100644
--- a/include/operators/gather.h
+++ b/include/operators/gather.h
@@ -3,10 +3,24 @@
 #include "core/operator.h"
 
 namespace infini {
+/**
+ * @brief Gather and concatenate given positions on a certain dimension of the
+ * input tensor using an index tensor.
+ *
+ */
 class GatherObj : public OperatorObj {
     int axis;
 
   public:
+    /**
+     * @brief Construct a new Gather object.
+     *
+     * @param graph The computation graph that this operator belongs to.
+     * @param input The input tensor.
+     * @param index The index tensor.
+     * @param output The output tensor.
+     * @param axis The axis to gather on.
+     */
     GatherObj(GraphObj *graph, Tensor input, Tensor index, Tensor output,
               int axis);
     OP_CLONE(GatherObj);
diff --git a/include/operators/matmul.h b/include/operators/matmul.h
index 0ddf494f..9c54d332 100644
--- a/include/operators/matmul.h
+++ b/include/operators/matmul.h
@@ -2,7 +2,10 @@
 #include "core/operator.h"
 
 namespace infini {
-
+/**
+ * @brief Matrix multiplication.
+ *
+ */
 class MatmulObj : public OperatorObj {
   private:
     // InfiniTensor assumes a row-major tensor layout. `transA`=false means
@@ -16,15 +19,19 @@ class MatmulObj : public OperatorObj {
 
   public:
     /**
-     * @brief This comments show how operators is defined in InfiniTensor. The
-     * constructor can create output tensors for the operator or not, which
-     * depends on `graph`.
+     * @brief Construct a new Matmul object. This comments show how operators is
+     * defined in InfiniTensor. The constructor can create output tensors for
+     * the operator or not, which depends on `graph`.
      *
-     * @param graph If graph is not empty, create outputs in the constructor.
-     * Otherwise, check the provided shape with the results of `inferShape` in
-     * `checkValid`.
+     * @param graph The computation graph that this operator belongs to.
+     * @param A The input tensor.
+     * @param B The input tensor.
      * @param C C is the output of Matmul. If outputs are going to be created in
      * the constructor, C should be an empty Ref.
+     * @param transA If matrix A should be transposed when computing.
+     * @param transB If matrix B should be transposed when computing.
+     * @param bias The bias tensor.
+     * @param act The activation function.
      */
     MatmulObj(GraphObj *graph, Tensor A, Tensor B, Tensor C,
               bool transA = false, bool transB = false, Tensor bias = nullptr,
diff --git a/include/operators/pad.h b/include/operators/pad.h
index 1b483f18..4df709d2 100644
--- a/include/operators/pad.h
+++ b/include/operators/pad.h
@@ -2,12 +2,27 @@
 #include "core/operator.h"
 
 namespace infini {
+/**
+ * @brief Add data at the out side of a tensor.
+ *
+ */
 class PadObj : public OperatorObj {
     // the number of start and end pad values for all dims.
     vector<int> pads;
 
   public:
     // pad for appointed axises,if axis is empty,then pad for all axises.
+    /**
+     * @brief Construct a new Pad object.
+     *
+     * @param graph The computation graph that this operator belongs to.
+     * @param input The input tensor.
+     * @param output The padded tensor.
+     * @param pads Add padding elements at the begining and end of each axis.
+     * Suppose that padding axes are [x1, x2, ...], then pads's format is
+     * [x1_begin, x2_begin, ..., x1_end, x2_end, ...]
+     * @param axis Pad for appointed axes. If axis is empty, pad for all axes.
+     */
     PadObj(GraphObj *graph, Tensor input, Tensor output,
            const vector<int> &pads, const optional<const vector<int>> &axis);
     OP_CLONE(PadObj);
diff --git a/include/operators/pooling.h b/include/operators/pooling.h
index 9ecd20f3..c14bb8ad 100644
--- a/include/operators/pooling.h
+++ b/include/operators/pooling.h
@@ -2,7 +2,10 @@
 #include "core/operator.h"
 
 namespace infini {
-
+/**
+ * @brief The base class for AvgPool and MaxPool.
+ *
+ */
 class PoolingObj : public OperatorObj {
   private:
     int kh, kw;
@@ -12,6 +15,24 @@ class PoolingObj : public OperatorObj {
     int n, c, h, w;
 
   public:
+    /**
+     * @brief Construct a new Pooling object.
+     *
+     * @param graph The computation graph that this operator belongs to.
+     * @param optype Operator type of this pooling operator.
+     * @param input The input tensor.
+     * @param output The output tensor.
+     * @param kh Kernel height.
+     * @param kw Kernel width.
+     * FIXME: Dilated pooling is not supported for many frameworks?
+     * @param dh Dilation at the height dimension.
+     * @param dw Dilation at the width dimension.
+     * FIXME: Auto padding using padding mode.
+     * @param ph Padding at the height dimension.
+     * @param pw Padding at the width dimension.
+     * @param sh Stride at the height dimension.
+     * @param sw Stride at the width dimension.
+     */
     PoolingObj(GraphObj *graph, OpType optype, Tensor input, Tensor output,
                int kh, int kw, int dh, int dw, int ph, int pw, int sh, int sw);
     OP_CLONE(PoolingObj);
diff --git a/include/operators/reduce_mean.h b/include/operators/reduce_mean.h
index f2337bba..cfa4eccc 100644
--- a/include/operators/reduce_mean.h
+++ b/include/operators/reduce_mean.h
@@ -2,11 +2,24 @@
 #include "core/operator.h"
 
 namespace infini {
+/**
+ * @brief Compute the mean of input tensor's elements along certain axes.
+ *
+ */
 class ReduceMeanObj : public OperatorObj {
     set<int> axis; // axis to reduce
     bool keepDims;
 
   public:
+    /**
+     * @brief Construct a new ReduceMean object.
+     *
+     * @param graph The computation graph that this operator belongs to.
+     * @param input The input tensor.
+     * @param output The output tensor.
+     * @param axis Axes to reduce.
+     * @param keepDims Keep the reduced dimensions or not.
+     */
     ReduceMeanObj(GraphObj *graph, Tensor input, Tensor output,
                   const optional<const vector<int>> &axis,
                   bool keepDims = true);
diff --git a/include/operators/reshape.h b/include/operators/reshape.h
index e529c3a5..324c5374 100644
--- a/include/operators/reshape.h
+++ b/include/operators/reshape.h
@@ -3,10 +3,22 @@
 #include "core/operator.h"
 
 namespace infini {
+/**
+ * @brief Change the shape of the input tensor.
+ *
+ */
 class ReshapeObj : public OperatorObj {
     Shape dims;
 
   public:
+    /**
+     * @brief Construct a new Reshape object.
+     *
+     * @param graph The computation graph that this operator belongs to.
+     * @param input The input tensor.
+     * @param output The output tensor.
+     * @param dims The shape of the output tensor.
+     */
     ReshapeObj(GraphObj *graph, Tensor input, Tensor output, const Shape &dims);
     OP_CLONE(ReshapeObj);
 
@@ -21,9 +33,22 @@ class ReshapeObj : public OperatorObj {
     vector<int> getOpAttrVector() const override;
 };
 
+/**
+ * @brief Reshape the input tensor into a one-dimensional tensor.
+ * FIXME: Move to an independent file.
+ * FIXME: Different parameter list with ONNX and Pytorch.
+ *
+ */
 class FlattenObj : public OperatorObj {
 
   public:
+    /**
+     * @brief Construct a new Flatten object.
+     *
+     * @param graph The computation graph that this operator belongs to.
+     * @param input The input tensor.
+     * @param output The output one-dimensional tensor.
+     */
     FlattenObj(GraphObj *graph, Tensor input, Tensor output);
     OP_CLONE(FlattenObj);
 
@@ -38,9 +63,21 @@ class FlattenObj : public OperatorObj {
     vector<int> getOpAttrVector() const override;
 };
 
+/**
+ * @brief Copy the input tensor.
+ * FIXME: Move to an independent file.
+ *
+ */
 class IdentityObj : public OperatorObj {
 
   public:
+    /**
+     * @brief Construct a new Identity object.
+     *
+     * @param graph The computation graph that this operator belongs to.
+     * @param input The input tensor.
+     * @param output The output tensor, which is the same as the input tensor.
+     */
     IdentityObj(GraphObj *graph, Tensor input, Tensor output);
     OP_CLONE(IdentityObj);
 
diff --git a/include/operators/resize.h b/include/operators/resize.h
index 33718f85..4cc328dc 100644
--- a/include/operators/resize.h
+++ b/include/operators/resize.h
@@ -3,6 +3,11 @@
 #include "core/operator.h"
 
 namespace infini {
+/**
+ * @brief Resize the input tensor. See
+ * https://github.com/onnx/onnx/blob/main/docs/Operators.md#Resize for detail.
+ *
+ */
 class ResizeObj : public OperatorObj {
   public:
     enum class ECoordinateTransMode {
diff --git a/include/operators/slice.h b/include/operators/slice.h
index 3a407716..e7262552 100644
--- a/include/operators/slice.h
+++ b/include/operators/slice.h
@@ -2,10 +2,29 @@
 #include "core/operator.h"
 
 namespace infini {
+/**
+ * @brief Produce a slice of the input tensor along given dimensions.
+ *
+ */
 class SliceObj : public OperatorObj {
     vector<int> starts, ends; // the start no. and end no. for all dims.
 
   public:
+    /**
+     * @brief Construct a new Slice object.
+     *
+     * @param graph The computation graph that this operator belongs to.
+     * @param input The input tensor.
+     * @param output The output tensor.
+     * @param starts The start position to slice at certain axes. `starts` is a
+     * list which has the same length with axis.
+     * @param ends The end position to slice at certain axes. `ends` is a list
+     * which has the same length with axis.
+     * @param axis The dimensions to slice. If `axis` is empty, it is set to [0,
+     * 1, ..., d-1], where d is the number of dimensions of the input tensor.
+     * @param steps The step to slice at certain axes. `step` is a list which
+     * has the same length with axis.
+     */
     SliceObj(GraphObj *graph, Tensor input, Tensor output,
              const vector<int> &starts, const vector<int> &ends,
              const optional<vector<int>> &axis,
diff --git a/include/operators/split.h b/include/operators/split.h
index b850df34..e2f9f4a3 100644
--- a/include/operators/split.h
+++ b/include/operators/split.h
@@ -2,12 +2,37 @@
 #include "core/operator.h"
 
 namespace infini {
+/**
+ * @brief Split a tensor into multiple ones.
+ *
+ */
 class SplitObj : public OperatorObj {
     int dim, num;      // split dim;Average split num or outputs size
     vector<int> ratio; // output dim ratio
   public:
+    /**
+     * @brief Construct a new Split object.
+     *
+     * @param graph The computation graph that this operator belongs to.
+     * @param input The input tensor.
+     * @param outputs The output tensors after splitting.
+     * @param dim The dimension to split.
+     * @param num The number of output tensors. The input tensor is split into
+     * `num` evenly chunk along dimension `dim. The last chunk will be smaller
+     * if the input tensor cannot be evenly split.
+     */
     SplitObj(GraphObj *graph, Tensor input, std::optional<TensorVec> outputs,
              int dim, int num);
+    /**
+     * @brief Construct a new Split object.
+     *
+     * @param graph The computation graph that this operator belongs to.
+     * @param input The input tensor.
+     * @param outputs The output tensors after splitting.
+     * @param dim The dimension to split.
+     * @param ratio The size of dimension `dim` for the output tensors after
+     * splitting.
+     */
     SplitObj(GraphObj *graph, Tensor input, std::optional<TensorVec> outputs,
              int dim, const vector<int> &ratio);
     OP_CLONE(SplitObj);
diff --git a/include/operators/unary.h b/include/operators/unary.h
index be7cc69f..111a9314 100644
--- a/include/operators/unary.h
+++ b/include/operators/unary.h
@@ -2,8 +2,20 @@
 #include "core/operator.h"
 
 namespace infini {
+/**
+ * @brief The base class for unary operators.
+ *
+ */
 class UnaryObj : public OperatorObj {
   public:
+    /**
+     * @brief Construct a new Unary object.
+     *
+     * @param type Operator type.
+     * @param graph The computation graph that this operator belongs to.
+     * @param input The input tensor.
+     * @param output The output tensor.
+     */
     UnaryObj(OpType type, GraphObj *graph, Tensor input, Tensor output);
     optional<vector<Shape>> inferShape(const TensorVec &inputs) const override;