diff --git a/snake.py b/snake.py
index 9a4bf0a..e0027ba 100644
--- a/snake.py
+++ b/snake.py
@@ -31,7 +31,7 @@ while True:
     for event in pygame.event.get():
         if event.type == locals.QUIT:
             # 接收到退出事件后退出程序
-            exit()
+                exit()
         if event.type == locals.KEYDOWN:
             if event.key == locals.K_RIGHT and setheading != "left":
                 setheading = 'right'
@@ -73,6 +73,9 @@ while True:
     text = my_font.render(info,True,(0,0,0))
     screen.blit(text,(500,10))
     # 将果实画上去
+    if x<0 or x>630 or y<0 or y>450:
+        score=0
+        exit()
     screen.blit(food, (apple_x, apple_y))
     # 刷新画面
     pygame.display.update()