diff --git a/src/toast/type.ts b/src/toast/type.ts
index 0722f7a9..da6250e5 100644
--- a/src/toast/type.ts
+++ b/src/toast/type.ts
@@ -39,5 +39,5 @@ export interface TdToastProps {
   /**
    * 防止滚动穿透
    */
-  preventScrollThrough: boolean;
+  preventScrollThrough?: boolean;
 }