diff --git a/packages/field/index.wxs b/packages/field/index.wxs
index 51b03781..639ae2f7 100644
--- a/packages/field/index.wxs
+++ b/packages/field/index.wxs
@@ -2,7 +2,7 @@
 var utils = require('../wxs/utils.wxs');
 
 function inputStyle(autosize) {
-  if (autosize.constructor === 'Object') {
+  if (autosize && autosize.constructor === 'Object') {
     var style = '';
     if (autosize.minHeight) {
       style += 'min-height:' + utils.addUnit(autosize.minHeight) + ';';