diff --git a/Deploy/db/registry.sql b/Deploy/db/registry.sql
index b661321d7..4380d3192 100644
--- a/Deploy/db/registry.sql
+++ b/Deploy/db/registry.sql
@@ -38,8 +38,14 @@ insert into role (role_code, name) values
 
 create table user (
  user_id int NOT NULL AUTO_INCREMENT,
- username varchar(15),
- email varchar(128),
+# The max length of username controlled by API is 20, 
+# and 11 is reserved for marking the deleted users.
+# The mark of deleted user is "#user_id".
+# The 11 consist of 10 for the max value of user_id(4294967295)  
+# in MySQL and 1 of '#'.
+ username varchar(32),
+# 11 bytes is reserved for marking the deleted users.
+ email varchar(255),
  password varchar(40) NOT NULL,
  realname varchar (20) NOT NULL,
  comment varchar (30),
diff --git a/dao/dao_test.go b/dao/dao_test.go
index f823e9a6c..405eff79b 100644
--- a/dao/dao_test.go
+++ b/dao/dao_test.go
@@ -889,20 +889,6 @@ func TestGetTopRepos(t *testing.T) {
 	}
 }
 
-func TestDeleteUser(t *testing.T) {
-	err := DeleteUser(currentUser.UserID)
-	if err != nil {
-		t.Errorf("Error occurred in DeleteUser: %v", err)
-	}
-	user, err := GetUser(*currentUser)
-	if err != nil {
-		t.Errorf("Error occurred in GetUser: %v", err)
-	}
-	if user != nil {
-		t.Errorf("user is not nil after deletion, user: %+v", user)
-	}
-}
-
 var targetID, policyID, policyID2, policyID3, jobID, jobID2, jobID3 int64
 
 func TestAddRepTarget(t *testing.T) {
diff --git a/dao/user.go b/dao/user.go
index 3022b55a8..6f928bdac 100644
--- a/dao/user.go
+++ b/dao/user.go
@@ -214,7 +214,10 @@ func CheckUserPassword(query models.User) (*models.User, error) {
 // DeleteUser ...
 func DeleteUser(userID int) error {
 	o := GetOrmer()
-	_, err := o.Raw(`update user set deleted = 1 where user_id = ?`, userID).Exec()
+	_, err := o.Raw(`update user 
+		set deleted = 1, username = concat(username, "#", user_id),
+			email = concat(email, "#", user_id)
+		where user_id = ?`, userID).Exec()
 	return err
 }
 
diff --git a/dao/user_test.go b/dao/user_test.go
new file mode 100644
index 000000000..6a8bd4874
--- /dev/null
+++ b/dao/user_test.go
@@ -0,0 +1,69 @@
+/*
+   Copyright (c) 2016 VMware, Inc. All Rights Reserved.
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package dao
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/vmware/harbor/models"
+)
+
+func TestDeleteUser(t *testing.T) {
+	username := "user_for_test"
+	email := "user_for_test@vmware.com"
+	password := "P@ssword"
+	realname := "user_for_test"
+
+	u := models.User{
+		Username: username,
+		Email:    email,
+		Password: password,
+		Realname: realname,
+	}
+	id, err := Register(u)
+	if err != nil {
+		t.Fatalf("failed to register user: %v", err)
+	}
+
+	err = DeleteUser(int(id))
+	if err != nil {
+		t.Fatalf("Error occurred in DeleteUser: %v", err)
+	}
+
+	user := &models.User{}
+	sql := "select * from user where user_id = ?"
+	if err = GetOrmer().Raw(sql, id).
+		QueryRow(user); err != nil {
+		t.Fatalf("failed to query user: %v", err)
+	}
+
+	if user.Deleted != 1 {
+		t.Error("user is not deleted")
+	}
+
+	expected := fmt.Sprintf("%s#%d", u.Username, id)
+	if user.Username != expected {
+		t.Errorf("unexpected username: %s != %s", user.Username,
+			expected)
+	}
+
+	expected = fmt.Sprintf("%s#%d", u.Email, id)
+	if user.Email != expected {
+		t.Errorf("unexpected email: %s != %s", user.Email,
+			expected)
+	}
+}