diff --git a/components/_util/openAnimation.tsx b/components/_util/openAnimation.tsx
index ac1d6e5fdc..fc171830c8 100644
--- a/components/_util/openAnimation.tsx
+++ b/components/_util/openAnimation.tsx
@@ -13,7 +13,7 @@ function animate(node: HTMLElement, show: boolean, done: () => void) {
         node.style.opacity = '1';
       } else {
         height = node.offsetHeight;
-        node.style.height = '0 px';
+        node.style.height = '0px';
         node.style.opacity = '0';
       }
     },