diff --git a/src/ChineseChess.js b/src/ChineseChess.js
index 4fdf234..fe34fee 100644
--- a/src/ChineseChess.js
+++ b/src/ChineseChess.js
@@ -140,11 +140,11 @@ export class Chessboard {
             context.beginPath()
             
             // 棋盘描边
-            context.moveTo(10, 10)
-            context.lineTo(10, width * 9.6)
-            context.lineTo(width * 8.6, width * 9.6)
-            context.lineTo(width * 8.6, 10)
-            context.lineTo(10, 10)
+            context.moveTo(20, 20)
+            context.lineTo(20, width * 9.4)
+            context.lineTo(width * 8.4, width * 9.4)
+            context.lineTo(width * 8.4, 20)
+            context.lineTo(20, 20)
             context.stroke()
         };
         img.src = canvas.toDataURL()