diff --git a/packages/components/table/src/store/tree.ts b/packages/components/table/src/store/tree.ts
index 12097d4656..276d4bf2f6 100644
--- a/packages/components/table/src/store/tree.ts
+++ b/packages/components/table/src/store/tree.ts
@@ -77,8 +77,7 @@ function useTree<T>(watcherData: WatcherPropsData<T>) {
     const nested = normalizedData.value
     const normalizedLazyNode_ = normalizedLazyNode.value
     const newTreeData = {}
-    if (nested.size) {
-      const keys = Array.from(nested.keys())
+    if (nested instanceof Map && nested.size) {
       const oldTreeData = unref(treeData)
       const rootLazyRowKeys = []
       const getExpanded = (oldValue, key) => {
@@ -96,7 +95,7 @@ function useTree<T>(watcherData: WatcherPropsData<T>) {
         }
       }
       // 合并 expanded 与 display，确保数据刷新后，状态不变
-      keys.forEach((key) => {
+      nested.forEach((_, key) => {
         const oldValue = oldTreeData[key]
         const newValue = { ...nested.get(key) }
         newValue.expanded = getExpanded(oldValue, key)