diff --git a/docs/references/http_api_reference.md b/docs/references/http_api_reference.md
index 7af9d4bdf..f2b86a735 100644
--- a/docs/references/http_api_reference.md
+++ b/docs/references/http_api_reference.md
@@ -1840,7 +1840,7 @@ Retrieves chunks from specified datasets.
   - `"highlight"`: `boolean`
   - `"cross_languages"`: `list[string]`
   - `"metadata_condition"`: `object`
-
+  - `"use_kg"`: `boolean`
 ##### Request example
 
 ```bash
@@ -1888,6 +1888,8 @@ curl --request POST \
   The weight of vector cosine similarity. Defaults to `0.3`. If x represents the weight of vector cosine similarity, then (1 - x) is the term similarity weight.
 - `"top_k"`: (*Body parameter*), `integer`  
   The number of chunks engaged in vector cosine computation. Defaults to `1024`.
+- `"use_kg"`: (*Body parameter*), `boolean`  
+  The search includes text chunks related to the knowledge graph of the selected dataset to handle complex multi-hop queries. Defaults to `False`.
 - `"rerank_id"`: (*Body parameter*), `integer`  
   The ID of the rerank model.
 - `"keyword"`: (*Body parameter*), `boolean`  
diff --git a/rag/nlp/search.py b/rag/nlp/search.py
index 09c1324d3..1bf0abe04 100644
--- a/rag/nlp/search.py
+++ b/rag/nlp/search.py
@@ -384,7 +384,7 @@ class Dealer:
                                                    rank_feature=rank_feature)
         else:
             lower_case_doc_engine = os.getenv('DOC_ENGINE', 'elasticsearch')
-            if lower_case_doc_engine == "elasticsearch":
+            if lower_case_doc_engine in ["elasticsearch","opensearch"]:
                 # ElasticSearch doesn't normalize each way score before fusion.
                 sim, tsim, vsim = self.rerank(
                     sres, question, 1 - vector_similarity_weight, vector_similarity_weight,