diff --git a/my_Tetris.py b/my_Tetris.py
index 7004c59..e063cf2 100644
--- a/my_Tetris.py
+++ b/my_Tetris.py
@@ -72,7 +72,8 @@ while True:
                 center[0] = center[0] + 1
                 if check(center) == False:
                     center[0] = center[0] - 1
-            elif event.key == locals.K_UP:    # 向下
+            elif event.key == locals.K_UP:
+                old_index = index    # 向下
                 index += 1
                 if index >= len(shape):
                     index = 0