diff --git a/pkg/models/notifications.go b/pkg/models/notifications.go
index 08cf800..700d444 100644
--- a/pkg/models/notifications.go
+++ b/pkg/models/notifications.go
@@ -32,6 +32,6 @@ type NotificationSubscriber struct {
 
 	UserAgent string `json:"user_agent"`
 	Provider  string `json:"provider"`
-	DeviceID  string `json:"device_id"`
+	DeviceID  string `json:"device_id" gorm:"uniqueIndex"`
 	AccountID uint   `json:"account_id"`
 }
diff --git a/pkg/server/notifications_api.go b/pkg/server/notifications_api.go
index 750c608..187de8d 100644
--- a/pkg/server/notifications_api.go
+++ b/pkg/server/notifications_api.go
@@ -1,5 +1,6 @@
 package server
 
+import "C"
 import (
 	"code.smartsheep.studio/hydrogen/passport/pkg/database"
 	"code.smartsheep.studio/hydrogen/passport/pkg/models"
@@ -71,6 +72,14 @@ func addNotifySubscriber(c *fiber.Ctx) error {
 		return err
 	}
 
+	var count int64
+	if err := database.C.Where(&models.NotificationSubscriber{
+		DeviceID:  data.DeviceID,
+		AccountID: user.ID,
+	}).Model(&models.NotificationSubscriber{}).Count(&count).Error; err != nil || count > 0 {
+		return c.SendStatus(fiber.StatusOK)
+	}
+
 	subscriber, err := services.AddNotifySubscriber(
 		user,
 		data.Provider,