diff --git a/packages/mixins/transition.ts b/packages/mixins/transition.ts
index 044f6daa..c2fbce50 100644
--- a/packages/mixins/transition.ts
+++ b/packages/mixins/transition.ts
@@ -23,7 +23,6 @@ export function transition(showDefaultValue: boolean) {
       duration: {
         type: null,
         value: 300,
-        observer: 'observeDuration',
       },
       name: {
         type: String,