diff --git a/packages/vant-css/src/goods-action.css b/packages/vant-css/src/goods-action.css
index ca163bbdd..b473839cc 100644
--- a/packages/vant-css/src/goods-action.css
+++ b/packages/vant-css/src/goods-action.css
@@ -7,6 +7,10 @@
   display: flex;
   position: fixed;
 
+  &__big-btn {
+    flex: 1;
+  }
+
   &__mini-btn {
     color: #666;
     display: flex;