diff --git a/list.md b/list.md
index 8bbf091..31dd418 100644
--- a/list.md
+++ b/list.md
@@ -7,7 +7,7 @@
 - [x] `_tWinMain` - `src/source/Tetris.cpp`
 - [x] `MyRegisterClass` - `src/source/Tetris.cpp`
 - [x] `InitInstance` - `src/source/Tetris.cpp`
-- [ ] `WndProc` - `src/source/Tetris.cpp`
+- [x] `WndProc` - `src/source/Tetris.cpp`
 - [ ] `About` - `src/source/Tetris.cpp`
 
 ## 第二阶段：游戏区域与状态初始化
diff --git a/report/images/Part1/WndProcAfter.png b/report/images/Part1/WndProcAfter.png
new file mode 100644
index 0000000..67b8d3e
Binary files /dev/null and b/report/images/Part1/WndProcAfter.png differ
diff --git a/report/images/Part1/WndProcBefore.png b/report/images/Part1/WndProcBefore.png
new file mode 100644
index 0000000..eb32dfa
Binary files /dev/null and b/report/images/Part1/WndProcBefore.png differ
diff --git a/src/source/Tetris.cpp b/src/source/Tetris.cpp
index fb56eb4..fd3d091 100644
--- a/src/source/Tetris.cpp
+++ b/src/source/Tetris.cpp
@@ -104,7 +104,41 @@ BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
 LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
 {
     // TODO(作业4): 补全主窗口消息处理函数。
-    return DefWindowProc(hWnd, message, wParam, lParam);
+    switch (message)
+    {
+    case WM_COMMAND:
+    {
+        int wmId = LOWORD(wParam);
+
+        switch (wmId)
+        {
+        case IDM_ABOUT:
+            DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About);
+            break;
+        case IDM_EXIT:
+            DestroyWindow(hWnd);
+            break;
+        default:
+            return DefWindowProc(hWnd, message, wParam, lParam);
+        }
+    }
+    break;
+    case WM_PAINT:
+    {
+        PAINTSTRUCT ps;
+        HDC hdc = BeginPaint(hWnd, &ps);
+        TDrawScreen(hdc, hWnd);
+        EndPaint(hWnd, &ps);
+    }
+    break;
+    case WM_DESTROY:
+        PostQuitMessage(0);
+        break;
+    default:
+        return DefWindowProc(hWnd, message, wParam, lParam);
+    }
+
+    return 0;
 }
 
 INT_PTR CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)