diff --git a/lib/charts/bubble.js b/lib/charts/bubble.js
index 7c5a0774..d5da004b 100644
--- a/lib/charts/bubble.js
+++ b/lib/charts/bubble.js
@@ -72,7 +72,6 @@
              * @param {Number} c0 分组值
              * @param {String} time 时间值 
              */
-            this.formatter = {};
             this.formatter.tipFormat = function (key, x0, y0, r0, c0, time) {
                 var tpl = '<b>' + this.keyDimen + ':{key}</b><br />' + 
                     '<b>' + this.xDimen + ':{xDimen}</b><br/>' +