diff --git a/src/components/dropdown/dropdown.less b/src/components/dropdown/dropdown.less
index b69d9c9633..7c337ff174 100644
--- a/src/components/dropdown/dropdown.less
+++ b/src/components/dropdown/dropdown.less
@@ -78,7 +78,7 @@
     left: 0;
 
     .@{class-prefix-dropdown}-popup-mask {
-      position: absolute;
+      position: fixed;
     }
 
     .@{class-prefix-dropdown}-popup-body {