diff --git a/ship.py b/ship.py
index 6638dad..9ad7710 100644
--- a/ship.py
+++ b/ship.py
@@ -43,4 +43,8 @@ class Ship(Sprite):
         self.rect.centery = self.centery
 
     def blitme(self):
-        self.screen.blit(self.image, self.rect)
\ No newline at end of file
+        self.screen.blit(self.image, self.rect)
+
+    def center_ship(self):
+        """让飞船在屏幕上居中"""
+        self.center = self.screen_rect.centerx