diff --git a/src/Tetris/Board.java b/src/Tetris/Board.java
index 4b48eee..563b8ad 100644
--- a/src/Tetris/Board.java
+++ b/src/Tetris/Board.java
@@ -31,6 +31,7 @@ public class Board extends JPanel implements KeyListener
   private long beginTime;
   private int delayTime = normal;
   private int deltax = 0;
+  private boolean collision = false;
 
 
   public Board() {
@@ -40,6 +41,9 @@ public class Board extends JPanel implements KeyListener
 
       @Override
       public void actionPerformed(ActionEvent e) {
+        if(collision){
+          return;
+        }
         if(!(x + deltax + shape[0].length >11) && !(x + deltax<0))
         {
           x +=deltax;
@@ -47,8 +51,12 @@ public class Board extends JPanel implements KeyListener
 
         deltax= 0;
         if(System.currentTimeMillis() -beginTime > delayTime){
+            if(!(y+1+shape.length > BOARD_HEIGHT)){
+              y++;
+            }else{
+              collision=true;
+            }
 
-          y++;
           beginTime=System.currentTimeMillis();
         }