diff --git a/apps/terminal/api/session/sharing.py b/apps/terminal/api/session/sharing.py
index a3d324205..9a60734fa 100644
--- a/apps/terminal/api/session/sharing.py
+++ b/apps/terminal/api/session/sharing.py
@@ -1,8 +1,8 @@
-from rest_framework.exceptions import MethodNotAllowed, ValidationError
-from rest_framework.decorators import action
-from rest_framework.response import Response
 from django.conf import settings
 from django.utils.translation import ugettext_lazy as _
+from rest_framework.decorators import action
+from rest_framework.exceptions import MethodNotAllowed, ValidationError
+from rest_framework.response import Response
 
 from common.const.http import PATCH
 from orgs.mixins.api import OrgModelViewSet
diff --git a/apps/terminal/models/session/sharing.py b/apps/terminal/models/session/sharing.py
index a62e23a85..c0e83dfda 100644
--- a/apps/terminal/models/session/sharing.py
+++ b/apps/terminal/models/session/sharing.py
@@ -133,6 +133,13 @@ class SessionJoinRecord(JMSBaseModel, OrgModelMixin):
         # self
         if self.verify_code != self.sharing.verify_code:
             return False, _('Invalid verification code')
+
+        # Link can only be joined once by the same user.
+        queryset = SessionJoinRecord.objects.filter(
+            verify_code=self.verify_code, sharing=self.sharing,
+            joiner=self.joiner, date_joined__lt=self.date_joined)
+        if queryset.exists():
+            return False, _('You have already joined this session')
         return True, ''
 
     def join_failed(self, reason):