diff --git a/pymilvus/client/prepare.py b/pymilvus/client/prepare.py
index cebcb27ea..8c4e6666a 100644
--- a/pymilvus/client/prepare.py
+++ b/pymilvus/client/prepare.py
@@ -1002,13 +1002,13 @@ def search_requests_with_expr(
         # no more parameters will be written searchParams.params
         # to ensure compatibility and milvus can still get a json format parameter
         # try to write all the parameters under searchParams into searchParams.Params
-        for key, value in search_params.items():
+        for key, value in param.items():
             if key in params:
                 if params[key] != value:
                     raise ParamError(
                         message=f"ambiguous parameter: {key}, in search_param: {value}, in search_param.params: {params[key]}"
                     )
-            else:
+            elif key != "params":
                 params[key] = value
         search_params["params"] = params