diff --git a/packages/vant-css/src/nav-bar.css b/packages/vant-css/src/nav-bar.css
index ec2c00fd0..c3b43fef7 100644
--- a/packages/vant-css/src/nav-bar.css
+++ b/packages/vant-css/src/nav-bar.css
@@ -33,6 +33,7 @@
     margin: 0 auto;
     max-width: 60%;
     font-size: 16px;
+    font-weight: 500;
   }
 
   &__left,