diff --git a/libs/milvus/langchain_milvus/vectorstores/milvus.py b/libs/milvus/langchain_milvus/vectorstores/milvus.py
index bbcef1d..c1e4958 100644
--- a/libs/milvus/langchain_milvus/vectorstores/milvus.py
+++ b/libs/milvus/langchain_milvus/vectorstores/milvus.py
@@ -1320,7 +1320,7 @@ def max_marginal_relevance_search_by_vector(
         """
         col_search_res = self._collection_search(
             embedding=embedding,
-            k=fetch_k,
+            k=k,
             param=param,
             expr=expr,
             timeout=timeout,