diff --git a/seahub/api2/serializers.py b/seahub/api2/serializers.py
index 305123e895..1c734f581b 100644
--- a/seahub/api2/serializers.py
+++ b/seahub/api2/serializers.py
@@ -1,11 +1,9 @@
-import re
-
 from rest_framework import serializers
 
 from seahub.auth import authenticate
 from seahub.api2.models import Token, TokenV2, DESKTOP_PLATFORMS
 from seahub.api2.utils import get_token_v1, get_token_v2
-from seahub.utils import is_valid_username
+from seahub.profile.models import Profile
 
 def all_none(values):
     for value in values:
@@ -35,7 +33,7 @@ class AuthTokenSerializer(serializers.Serializer):
     platform_version = serializers.CharField(required=False)
 
     def validate(self, attrs):
-        username = attrs.get('username')
+        login_id = attrs.get('username')
         password = attrs.get('password')
 
         platform = attrs.get('platform', None)
@@ -54,10 +52,9 @@ class AuthTokenSerializer(serializers.Serializer):
         else:
             raise serializers.ValidationError('invalid params')
 
-        # first check username and password
-        if username:
-            if not is_valid_username(username):
-                raise serializers.ValidationError('username is not valid.')
+        username = Profile.objects.get_username_by_login_id(login_id)
+        if username is None:
+            username = login_id
 
         if username and password:
             user = authenticate(username=username, password=password)
diff --git a/seahub/profile/models.py b/seahub/profile/models.py
index 25c3ac1966..56bf1be189 100644
--- a/seahub/profile/models.py
+++ b/seahub/profile/models.py
@@ -47,6 +47,9 @@ class ProfileManager(models.Manager):
     def get_username_by_login_id(self, login_id):
         """Convert a user's login id to username(login email).
         """
+        if not login_id:
+            return None
+
         try:
             return super(ProfileManager, self).get(login_id=login_id).user
         except Profile.DoesNotExist:
@@ -55,7 +58,7 @@ class ProfileManager(models.Manager):
     def get_user_language(self, username):
         """Get user's language from profile. Return default language code if
         user has no preferred language.
-        
+
         Arguments:
         - `self`:
         - `username`:
diff --git a/tests/api/test_obtain_auth_token.py b/tests/api/test_obtain_auth_token.py
new file mode 100644
index 0000000000..4a27328bbe
--- /dev/null
+++ b/tests/api/test_obtain_auth_token.py
@@ -0,0 +1,54 @@
+import json
+
+from seahub.profile.models import Profile
+from seahub.test_utils import BaseTestCase
+from .urls import TOKEN_URL
+
+class ObtainAuthTokenTest(BaseTestCase):
+    def setUp(self):
+        self.p = Profile.objects.add_or_update(self.user.username, '', '')
+        self.p.login_id = 'test_login_id'
+        self.p.save()
+
+    def test_correct_email_passwd(self):
+        resp = self.client.post(TOKEN_URL, {
+            'username': self.user.username,
+            'password': self.user_password,
+        })
+
+        json_resp = json.loads(resp.content)
+        assert json_resp['token'] is not None
+        assert len(json_resp['token']) == 40
+
+    def test_correct_loginID_password(self):
+
+        resp = self.client.post(TOKEN_URL, {
+            'username': self.p.login_id,
+            'password': self.user_password,
+        })
+
+        json_resp = json.loads(resp.content)
+        assert json_resp['token'] is not None
+        assert len(json_resp['token']) == 40
+
+    def test_invalid_password(self):
+        resp = self.client.post(TOKEN_URL, {
+            'username': self.user.username,
+            'password': 'random_password',
+        })
+        self.assertEqual(400, resp.status_code)
+        json_resp = json.loads(resp.content)
+        assert json_resp['non_field_errors'] == ['Unable to login with provided credentials.']
+
+    def test_empty_login_id(self):
+        self.p.login_id = ""
+        self.p.save()
+
+        resp = self.client.post(TOKEN_URL, {
+            'username': self.p.login_id,
+            'password': self.user_password,
+        })
+
+        self.assertEqual(400, resp.status_code)
+        json_resp = json.loads(resp.content)
+        assert json_resp['non_field_errors'] == ['Must include "username" and "password"']