diff --git a/include/operators/reduce_mean.h b/include/operators/reduce_mean.h
index 76d3454b..ef74cd2e 100644
--- a/include/operators/reduce_mean.h
+++ b/include/operators/reduce_mean.h
@@ -30,6 +30,7 @@ class ReduceMeanObj : public OperatorObj {
     int numOutputs() const override { return 1; }
 
     bool isReduced(int idx) const;
+    const set<int> &getAxes() const { return axes; }
     bool getKeepDims() const { return keepDims; }
 
   private:
diff --git a/pyinfinitensor/src/pyinfinitensor/onnx.py b/pyinfinitensor/src/pyinfinitensor/onnx.py
index bb155a6c..bd0b926a 100644
--- a/pyinfinitensor/src/pyinfinitensor/onnx.py
+++ b/pyinfinitensor/src/pyinfinitensor/onnx.py
@@ -456,8 +456,8 @@ def to_onnx(graph: backend.GraphHandler, name: str) -> ModelProto:
                     name,
                     "shape",
                     TensorProto.INT32,
-                    shape=[len(shape)],
-                    vals=shape,
+                    [len(shape)],
+                    shape,
                 )
             )
             ctx.push_node(make_node(ty.name, inputs, outputs, name))
@@ -468,7 +468,11 @@ def to_onnx(graph: backend.GraphHandler, name: str) -> ModelProto:
             axis = backend.gather_axis_of(op)
             ctx.push_node(make_node(ty.name, inputs, outputs, name, axis=axis))
         elif ty == backend.OpType.ReduceMean:
-            raise Exception("TODO")
+            axes = backend.reduce_mean_axes_of(op)
+            inputs.append(
+                ctx.push_data_input(name, "axes", TensorProto.INT32, [len(axes)], axes)
+            )
+            ctx.push_node(make_node(ty.name, inputs, outputs, name, keepdims=1))
         elif ty == backend.OpType.Slice:
             raise Exception("TODO")
         elif ty == backend.OpType.Pad:
diff --git a/src/ffi/ffi_infinitensor.cc b/src/ffi/ffi_infinitensor.cc
index c2d35051..09fa361c 100644
--- a/src/ffi/ffi_infinitensor.cc
+++ b/src/ffi/ffi_infinitensor.cc
@@ -1,6 +1,7 @@
 #include "core/graph_handler.h"
 #include "operators/concat.h"
 #include "operators/gather.h"
+#include "operators/reduce_mean.h"
 #include "operators/reshape.h"
 #include <pybind11/stl.h>
 
@@ -24,7 +25,7 @@ void register_operator_timer(py::module &m) {
 #endif
 }
 
-void init_values(py::module &m) {
+void export_values(py::module &m) {
 #define VALUE(TYPE, NAME) value(#NAME, TYPE::NAME)
 
     py::enum_<ActType>(m, "ActType")
@@ -103,20 +104,31 @@ static int gather_axis_of(Operator op) {
     return dynamic_cast<const GatherObj *>(op.get())->getAxis();
 }
 
+static vector<int> reduce_mean_axes_of(Operator op) {
+    IT_ASSERT(op->getOpType() == OpType::ReduceMean);
+    auto &set = dynamic_cast<const ReduceMeanObj *>(op.get())->getAxes();
+    return vector(set.begin(), set.end());
+}
+
 static Shape reshape_shape_of(Operator op) {
     IT_ASSERT(op->getOpType() == OpType::Reshape);
     return dynamic_cast<const ReshapeObj *>(op.get())->getShape();
 }
 
-void init_graph_builder(py::module &m) {
+void export_functions(py::module &m) {
+#define FUNCTION(NAME) def(#NAME, &NAME)
+    m.def("cpu_runtime", &CpuRuntimeObj::getInstance)
+        .FUNCTION(tensor_dtype)
+        .FUNCTION(reshape_shape_of)
+        .FUNCTION(concat_axis_of)
+        .FUNCTION(gather_axis_of)
+        .FUNCTION(reduce_mean_axes_of);
+#undef FUNCTION
+}
 
+void init_graph_builder(py::module &m) {
     using Handler = GraphHandlerObj;
 
-    m.def("cpu_runtime", &CpuRuntimeObj::getInstance)
-        .def("tensor_dtype", &tensor_dtype)
-        .def("reshape_shape_of", &reshape_shape_of)
-        .def("concat_axis_of", &concat_axis_of)
-        .def("gather_axis_of", &gather_axis_of);
     py::class_<RuntimeObj, std::shared_ptr<RuntimeObj>>(m, "Runtime");
     py::class_<CpuRuntimeObj, std::shared_ptr<CpuRuntimeObj>, RuntimeObj>(
         m, "CpuRuntime");
@@ -166,6 +178,7 @@ void init_graph_builder(py::module &m) {
 
 PYBIND11_MODULE(backend, m) {
     infini::register_operator_timer(m);
-    infini::init_values(m);
+    infini::export_values(m);
+    infini::export_functions(m);
     infini::init_graph_builder(m);
 }