diff --git a/packages/vant/src/floating-bubble/types.ts b/packages/vant/src/floating-bubble/types.ts
index 6790de03e..0d42978f6 100644
--- a/packages/vant/src/floating-bubble/types.ts
+++ b/packages/vant/src/floating-bubble/types.ts
@@ -2,7 +2,7 @@ export type FloatingBubbleThemeVars = {
   floatingBubbleSize?: string;
   floatingBubbleInitialGap?: string;
   floatingBubbleIconSize?: string;
-  floatingBubbleBackground: string;
+  floatingBubbleBackground?: string;
   floatingBubbleColor?: string;
   floatingBubbleZIndex?: number | string;
 };