diff --git a/qlib/workflow/__init__.py b/qlib/workflow/__init__.py
index 7cb1cf5cb..8135bab60 100644
--- a/qlib/workflow/__init__.py
+++ b/qlib/workflow/__init__.py
@@ -23,6 +23,7 @@ class QlibRecorder:
     @contextmanager
     def start(
         self,
+        *,
         experiment_id: Optional[Text] = None,
         experiment_name: Optional[Text] = None,
         recorder_id: Optional[Text] = None,
@@ -63,7 +64,14 @@ class QlibRecorder:
         resume : bool
             whether to resume the specific recorder with given name under the given experiment.
         """
-        run = self.start_exp(experiment_id, experiment_name, recorder_id, recorder_name, uri, resume)
+        run = self.start_exp(
+            experiment_id=experiment_id,
+            experiment_name=experiment_name,
+            recorder_id=recorder_id,
+            recorder_name=recorder_name,
+            uri=uri,
+            resume=resume,
+        )
         try:
             yield run
         except Exception as e:
@@ -72,7 +80,7 @@ class QlibRecorder:
         self.end_exp(Recorder.STATUS_FI)
 
     def start_exp(
-        self, experiment_id=None, experiment_name=None, recorder_id=None, recorder_name=None, uri=None, resume=False
+        self, *, experiment_id=None, experiment_name=None, recorder_id=None, recorder_name=None, uri=None, resume=False
     ):
         """
         Lower level method for starting an experiment. When use this method, one should end the experiment manually
@@ -105,7 +113,14 @@ class QlibRecorder:
         -------
         An experiment instance being started.
         """
-        return self.exp_manager.start_exp(experiment_id, experiment_name, recorder_id, recorder_name, uri, resume)
+        return self.exp_manager.start_exp(
+            experiment_id=experiment_id,
+            experiment_name=experiment_name,
+            recorder_id=recorder_id,
+            recorder_name=recorder_name,
+            uri=uri,
+            resume=resume,
+        )
 
     def end_exp(self, recorder_status=Recorder.STATUS_FI):
         """
diff --git a/qlib/workflow/exp.py b/qlib/workflow/exp.py
index 0a7e0a5a9..467c7c3f4 100644
--- a/qlib/workflow/exp.py
+++ b/qlib/workflow/exp.py
@@ -39,7 +39,7 @@ class Experiment:
         output["recorders"] = list(recorders.keys())
         return output
 
-    def start(self, recorder_id=None, recorder_name=None, resume=False):
+    def start(self, *, recorder_id=None, recorder_name=None, resume=False):
         """
         Start the experiment and set it to be active. This method will also start a new recorder.
 
@@ -240,7 +240,7 @@ class MLflowExperiment(Experiment):
     def __repr__(self):
         return "{name}(id={id}, info={info})".format(name=self.__class__.__name__, id=self.id, info=self.info)
 
-    def start(self, recorder_id=None, recorder_name=None, resume=False):
+    def start(self, *, recorder_id=None, recorder_name=None, resume=False):
         logger.info(f"Experiment {self.id} starts running ...")
         # Get or create recorder
         if recorder_name is None:
diff --git a/qlib/workflow/expm.py b/qlib/workflow/expm.py
index 5549bb9bf..04cc3bcb7 100644
--- a/qlib/workflow/expm.py
+++ b/qlib/workflow/expm.py
@@ -33,6 +33,7 @@ class ExpManager:
 
     def start_exp(
         self,
+        *,
         experiment_id: Optional[Text] = None,
         experiment_name: Optional[Text] = None,
         recorder_id: Optional[Text] = None,
@@ -304,6 +305,7 @@ class MLflowExpManager(ExpManager):
 
     def start_exp(
         self,
+        *,
         experiment_id: Optional[Text] = None,
         experiment_name: Optional[Text] = None,
         recorder_id: Optional[Text] = None,
@@ -320,7 +322,7 @@ class MLflowExpManager(ExpManager):
         # Set up active experiment
         self.active_experiment = experiment
         # Start the experiment
-        self.active_experiment.start(recorder_id, recorder_name, resume)
+        self.active_experiment.start(recorder_id=recorder_id, recorder_name=recorder_name, resume=resume)
 
         return self.active_experiment