diff --git a/frontend/src/network/network.ts b/frontend/src/network/network.ts
index 6696052..1502948 100644
--- a/frontend/src/network/network.ts
+++ b/frontend/src/network/network.ts
@@ -730,7 +730,10 @@ class Network {
     );
   }
 
-  async listUserCollections(username: string, page: number = 1): Promise<PageResponse<Collection>> {
+  async listUserCollections(
+    username: string,
+    page: number = 1,
+  ): Promise<PageResponse<Collection>> {
     return this._callApi(() =>
       axios.get(`${this.apiBaseUrl}/collection/list`, {
         params: { username, page },
@@ -776,10 +779,11 @@ class Network {
   async searchUserCollections(
     username: string,
     keyword: string,
+    excludedRID?: number,
   ): Promise<Response<Collection[]>> {
     return this._callApi(() =>
       axios.get(`${this.apiBaseUrl}/collection/search`, {
-        params: { username, keyword },
+        params: { username, keyword, excludedRID },
       }),
     );
   }
diff --git a/server/api/collection.go b/server/api/collection.go
index 533e42b..0746d63 100644
--- a/server/api/collection.go
+++ b/server/api/collection.go
@@ -202,7 +202,14 @@ func handleSearchUserCollections(c fiber.Ctx) error {
 	if username == "" {
 		return model.NewRequestError("username is required")
 	}
-	cols, err := service.SearchUserCollections(username, keyword)
+	excludedRIDStr := c.Query("excludedRID", "")
+	var excludedRID uint = 0
+	if excludedRIDStr != "" {
+		if rid, err := strconv.Atoi(excludedRIDStr); err == nil && rid > 0 {
+			excludedRID = uint(rid)
+		}
+	}
+	cols, err := service.SearchUserCollections(username, keyword, excludedRID)
 	if err != nil {
 		return err
 	}
diff --git a/server/dao/collection.go b/server/dao/collection.go
index 6c7d4d7..a4cc48e 100644
--- a/server/dao/collection.go
+++ b/server/dao/collection.go
@@ -176,14 +176,23 @@ func ListCollectionResources(collectionID uint, page int, pageSize int) ([]*mode
 }
 
 // SearchUserCollections searches for collections by user ID and keyword limited to 10 results.
-func SearchUserCollections(uid uint, keyword string) ([]*model.Collection, error) {
+// excludedRID: if >0, only return collections not containing this resource.
+func SearchUserCollections(uid uint, keyword string, excludedRID uint) ([]*model.Collection, error) {
 	var collections []*model.Collection
 
-	if err := db.
-		Model(&model.Collection{}).
+	query := db.Model(&model.Collection{}).
+		Where("user_id = ? AND title LIKE ?", uid, "%"+keyword+"%")
+
+	if excludedRID > 0 {
+		// Use LEFT JOIN with IS NULL for better performance
+		query = query.
+			Joins("LEFT JOIN collection_resources cr ON collections.id = cr.collection_id AND cr.resource_id = ?", excludedRID).
+			Where("cr.collection_id IS NULL")
+	}
+
+	if err := query.
 		Preload("Images").
 		Preload("Resources").
-		Where("user_id = ? AND title LIKE ?", uid, "%"+keyword+"%").
 		Limit(10).
 		Find(&collections).Error; err != nil {
 		return nil, err
diff --git a/server/service/collection.go b/server/service/collection.go
index e8b7edf..9cf4f0f 100644
--- a/server/service/collection.go
+++ b/server/service/collection.go
@@ -134,7 +134,8 @@ func ListCollectionResources(collectionID uint, page int) ([]*model.ResourceView
 }
 
 // Search user collections by keyword, limited to 10 results.
-func SearchUserCollections(username string, keyword string) ([]*model.CollectionView, error) {
+// excludedRID: if >0, only return collections not containing this resource.
+func SearchUserCollections(username string, keyword string, excludedRID uint) ([]*model.CollectionView, error) {
 	if username == "" || keyword == "" {
 		return nil, errors.New("invalid parameters")
 	}
@@ -143,7 +144,7 @@ func SearchUserCollections(username string, keyword string) ([]*model.Collection
 		return nil, err
 	}
 	uid := user.ID
-	collections, err := dao.SearchUserCollections(uid, keyword)
+	collections, err := dao.SearchUserCollections(uid, keyword, excludedRID)
 	if err != nil {
 		return nil, err
 	}