diff --git a/style/web/components/dialog/_index.less b/style/web/components/dialog/_index.less
index d7eb519325..e8c24cda10 100644
--- a/style/web/components/dialog/_index.less
+++ b/style/web/components/dialog/_index.less
@@ -105,7 +105,9 @@
 
     box-sizing: border-box;
     padding: @dialog-body-padding-fullscreen;
-    height: calc(100% - @dialog-header-height-fullscreen - @dialog-footer-height-fullscreen);
+    height: calc(
+      100% - @dialog-header-height-fullscreen - @dialog-footer-height-fullscreen
+    );
     overflow: auto;
   }
 
@@ -202,6 +204,7 @@
 
   // modeless 点击穿透 即可以操作背景后的元素
   &.@{prefix}-dialog__ctx--modeless {
+    position: fixed;
     pointer-events: none;
   }