diff --git a/my_Tetris.py b/my_Tetris.py
index 22e907a..d4ce3e7 100644
--- a/my_Tetris.py
+++ b/my_Tetris.py
@@ -53,17 +53,26 @@ current_shape=shape[index]
 
 color=random.choice(cube_colors)
 
+def check(center):
+    for cube in current_shape:
+        cube = (cube[0] + center[0] , cube[1] + center[1])
+        if cube[0] < 1 or cube[1] < 1 or cube[0] > grid_num_height  or cube[1] > grid_num_width:
+            return False
+
 while True:
     for event in pygame.event.get():
         if event.type == locals.QUIT:
             exit()
         if event.type == locals.KEYDOWN:
-            if event.key == locals.K_RIGHT:     # 向右
+            if event.key == locals.K_LEFT:     # 向右
+                center[1] = center[1]-1
+                if check(center) == False:
+                    center[1] = center[1]+1
+
+            elif event.key == locals.K_RIGHT:    # 向左
                 if center[1] < 15:
                     center[1] += 1
-            elif event.key == locals.K_LEFT:    # 向左
-                if center[1] > 1:
-                    center[1] -= 1
+
             elif event.key == locals.K_DOWN:    # 向下
                 if center[0] < 25:
                     center[0] += 1