diff --git a/npm/ng-packs/packages/components/tree/src/lib/components/tree.component.ts b/npm/ng-packs/packages/components/tree/src/lib/components/tree.component.ts
index 2980b7b5f0..63288a37d6 100644
--- a/npm/ng-packs/packages/components/tree/src/lib/components/tree.component.ts
+++ b/npm/ng-packs/packages/components/tree/src/lib/components/tree.component.ts
@@ -74,7 +74,7 @@ export class TreeComponent implements OnInit {
     const loaded$ = this.lazyLoadService.load(
       LOADING_STRATEGY.AppendAnonymousStyleToHead('ng-zorro-antd-tree.css'),
     );
-    subscriptionService.addOne(loaded$);
+    this.subscriptionService.addOne(loaded$);
   }
   
   onSelectedNodeChange(node) {