diff --git a/projects/ucap-webmessenger-ui-organization/src/lib/components/tree.component.ts b/projects/ucap-webmessenger-ui-organization/src/lib/components/tree.component.ts
index 172237e7..b680792b 100644
--- a/projects/ucap-webmessenger-ui-organization/src/lib/components/tree.component.ts
+++ b/projects/ucap-webmessenger-ui-organization/src/lib/components/tree.component.ts
@@ -5,7 +5,8 @@ import {
   ChangeDetectorRef,
   ViewChild,
   Output,
-  EventEmitter
+  EventEmitter,
+  AfterViewInit
 } from '@angular/core';
 import { DeptInfo } from '@ucap-webmessenger/protocol-query';
 import { MatTreeNestedDataSource, MatTree } from '@angular/material';
@@ -45,7 +46,7 @@ export class OraganizationNode {
   templateUrl: './tree.component.html',
   styleUrls: ['./tree.component.scss']
 })
-export class TreeComponent implements OnInit {
+export class TreeComponent implements OnInit, AfterViewInit {
   @Output()
   selected = new EventEmitter<DeptInfo>();
 
@@ -82,6 +83,7 @@ export class TreeComponent implements OnInit {
     });
 
     this.dataSource.data = rootNodeList;
+    this.treeControl.expand(this.dataSource.data[0]);
   }
 
   @ViewChild('orgranizationTree', { static: true })
@@ -104,6 +106,8 @@ export class TreeComponent implements OnInit {
 
   ngOnInit() {}
 
+  ngAfterViewInit(): void {}
+
   getChildren = (node: OraganizationNode) => node.children;
 
   hasChildren = (index: number, node: OraganizationNode) =>