diff --git a/packages/designer/src/builtin-simulator/bem-tools/bem-tools.less b/packages/designer/src/builtin-simulator/bem-tools/bem-tools.less
index 83a411e56..8c66e8513 100644
--- a/packages/designer/src/builtin-simulator/bem-tools/bem-tools.less
+++ b/packages/designer/src/builtin-simulator/bem-tools/bem-tools.less
@@ -6,5 +6,5 @@
   bottom: 0;
   right: 0;
   overflow: visible;
-  z-index: 800;
+  z-index: 1;
 }