diff --git a/2025.07.28_programming_with_cython/a.py b/2025.07.28_programming_with_cython/a.py
new file mode 100644
index 0000000..f6bcb06
--- /dev/null
+++ b/2025.07.28_programming_with_cython/a.py
@@ -0,0 +1,23 @@
+import example
+import time
+
+def py_calculate(n):
+    result = 0
+    for i in range(n):
+        result += i
+    return result
+
+n = 10**8
+
+start = time.time()
+py_result = py_calculate(n)
+print(py_result)
+py_time = time.time() - start
+
+start = time.time()
+cy_result = example.calculate(n)
+print(cy_result)
+cy_time = time.time() - start
+
+print(f"Python 版本: {py_time:.6f} 秒")
+print(f"Cython 版本: {cy_time:.6f} 秒")
\ No newline at end of file
diff --git a/2025.07.28_programming_with_cython/example.pyx b/2025.07.28_programming_with_cython/example.pyx
new file mode 100644
index 0000000..4138362
--- /dev/null
+++ b/2025.07.28_programming_with_cython/example.pyx
@@ -0,0 +1,11 @@
+def calculate(int n):
+    cdef int i
+
+    cdef long long result = 0
+    # cdef int result = 0  # 这个类型在数值比较大的时候会溢出，结果不正确。
+    # result = 0  # 这个不声明类型，使用 Python 的 int，Python 的整数是任意精度的，不会溢出，但性能会比 C 类型低。
+
+    for i in range(n):
+        result += i
+        
+    return result
\ No newline at end of file
diff --git a/2025.07.28_programming_with_cython/setup.py b/2025.07.28_programming_with_cython/setup.py
new file mode 100644
index 0000000..91eeb91
--- /dev/null
+++ b/2025.07.28_programming_with_cython/setup.py
@@ -0,0 +1,4 @@
+from distutils.core import setup
+from Cython.Build import cythonize
+
+setup(ext_modules=cythonize("example.pyx"))
\ No newline at end of file