diff --git a/Makefile b/Makefile
index c258ac2d..59842e9e 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-.PHONY : build clean install-python test-cpp test-onnx
+.PHONY : build clean format install-python test-cpp test-onnx
 
 TYPE ?= release
 CUDA ?= OFF
@@ -6,6 +6,7 @@ BANG ?= OFF
 INTELCPU ?= off
 BACKTRACE ?= ON
 TEST ?= ON
+FORMAT_ORIGIN ?=
 
 CMAKE_OPT = -DCMAKE_BUILD_TYPE=$(TYPE)
 CMAKE_OPT += -DUSE_CUDA=$(CUDA)
@@ -24,6 +25,9 @@ build:
 clean:
 	rm -rf build
 
+format:
+	@python3 scripts/format.py $(FORMAT_ORIGIN)
+
 install-python: build
 	cp build/$(TYPE)/backend*.so pyinfinitensor/src/pyinfinitensor
 	pip install pyinfinitensor/
diff --git a/scripts/format.py b/scripts/format.py
new file mode 100644
index 00000000..7d74d54b
--- /dev/null
+++ b/scripts/format.py
@@ -0,0 +1,50 @@
+import sys
+from pathlib import Path
+from subprocess import run
+
+c_style_file = [".h", ".hh", ".hpp", ".c", ".cc", ".cpp", ".cxx", ".cu", ".mlu"]
+py_file = ".py"
+proj_path = Path(sys.path[0]).parent
+
+
+# Formats one file under project path.
+def format_file(file):
+    file = Path(proj_path.joinpath(file))
+    if file.suffix in c_style_file:
+        run(f"clang-format-14 -i {file}", cwd=proj_path, shell=True)
+        run(f"git add {file}", cwd=proj_path, shell=True)
+    elif file.suffix == py_file:
+        run(f"black {file}", cwd=proj_path, shell=True)
+        run(f"git add {file}", cwd=proj_path, shell=True)
+
+
+if len(sys.argv) == 1:
+    # Last commit.
+    print("Formats git added files.")
+    for line in (
+        run("git status", cwd=proj_path, capture_output=True, shell=True)
+        .stdout.decode()
+        .splitlines()
+    ):
+        line = line.strip()
+        # Only formats git added files.
+        for pre in ["new file:", "modified:"]:
+            if line.startswith(pre):
+                format_file(line[len(pre) :].strip())
+            break
+else:
+    # Origin commit.
+    origin = sys.argv[1]
+    print(f'Formats changed files from "{origin}".')
+    for line in (
+        run(f"git diff {origin}", cwd=proj_path, capture_output=True, shell=True)
+        .stdout.decode()
+        .splitlines()
+    ):
+        diff = "diff --git "
+        if line.startswith(diff):
+            files = line[len(diff) :].split(" ")
+            assert len(files) == 2
+            assert files[0][:2] == "a/"
+            assert files[1][:2] == "b/"
+            format_file(files[1][2:])
diff --git a/test/script/clang_format_inplace.sh b/test/script/clang_format_inplace.sh
deleted file mode 100755
index 49b2e3d0..00000000
--- a/test/script/clang_format_inplace.sh
+++ /dev/null
@@ -1,4 +0,0 @@
-#!/usr/bin/env bash
-script_dir="$(cd -- "$(dirname -- "${BASH_SOURCE[0]:-$0}")" &>/dev/null && pwd 2>/dev/null)"
-PET_HOME="$(readlink -f ${script_dir}/../..)"
-find ${PET_HOME}/src ${PET_HOME}/include ${PET_HOME}/test  -iname *.h -o -iname *.cc | xargs clang-format -i