diff --git a/my_Tetris.py b/my_Tetris.py
index 6b16917..b4ba638 100644
--- a/my_Tetris.py
+++ b/my_Tetris.py
@@ -50,20 +50,28 @@ shape=random.choice(shape_list)
 index=random.randint(0,len(shape)-1)
 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 center[1] < 15:
-                    center[1] += 1
+            if event.key == locals.K_RIGHT:     # 向
+                center[1] += 1
+                if check(center)==False:
+                   center[1]-=1
             elif event.key == locals.K_LEFT:    # 向左
-                if center[1] > 1:
-                    center[1] -= 1
+                center[1] -= 1
+                if check(center)==False:
+                   center[1]+=1
             elif event.key == locals.K_DOWN:    # 向下
-                if center[0] < 25:
-                    center[0] += 1
+                center[0] += 1
+                if check(center)==False:
+                   center[0]+=1
 
     # 将背景图画上去
     screen.blit(background, (0, 0))