diff --git a/src/virtual.js b/src/virtual.js
index <HASH>..<HASH> 100644
--- a/src/virtual.js
+++ b/src/virtual.js
@@ -75,6 +75,14 @@ export default class Virtual {
 
   updateParam (key, value) {
     if (this.param && (key in this.param)) {
+      // if uniqueIds reducing, find out deleted id and remove from size map
+      if (key === 'uniqueIds' && (value.length < this.param[key].length)) {
+        this.sizes.forEach((v, key) => {
+          if (!value.includes(key)) {
+            this.sizes.delete(key)
+          }
+        })
+      }
       this.param[key] = value
     }
   }
Delete size map when items reducing