diff --git a/qlib/workflow/expm.py b/qlib/workflow/expm.py
index 82265b585..362b1a82b 100644
--- a/qlib/workflow/expm.py
+++ b/qlib/workflow/expm.py
@@ -7,8 +7,10 @@ from mlflow.entities import ViewType
 import os
 from pathlib import Path
 from contextlib import contextmanager
+from typing import Optional, Text
+
 from .exp import MLflowExperiment, Experiment
-from .recorder import Recorder, MLflowRecorder
+from .recorder import Recorder
 from ..log import get_module_logger
 
 logger = get_module_logger("workflow", "INFO")
@@ -20,16 +22,24 @@ class ExpManager:
     (The link: https://mlflow.org/docs/latest/python_api/mlflow.html)
     """
 
-    def __init__(self, uri, default_exp_name):
+    def __init__(self, uri: Text, default_exp_name: Optional[Text]):
         self._default_uri = uri
         self._current_uri = None
         self.default_exp_name = default_exp_name
         self.active_experiment = None  # only one experiment can active each time
 
     def __repr__(self):
-        return "{name}(default_uri={duri}, current_uri={curi})".format(name=self.__class__.__name__, duri=self._default_uri, curi=self._current_uri)
+        return "{name}(default_uri={duri}, current_uri={curi})".format(
+            name=self.__class__.__name__, duri=self._default_uri, curi=self._current_uri
+        )
 
-    def start_exp(self, experiment_name=None, recorder_name=None, uri=None, **kwargs):
+    def start_exp(
+        self,
+        experiment_name: Optional[Text] = None,
+        recorder_name: Optional[Text] = None,
+        uri: Optional[Text] = None,
+        **kwargs,
+    ):
         """
         Start an experiment. This method includes first get_or_create an experiment, and then
         set it to be active.
@@ -49,7 +59,7 @@ class ExpManager:
         """
         raise NotImplementedError(f"Please implement the `start_exp` method.")
 
-    def end_exp(self, recorder_status: str = Recorder.STATUS_S, **kwargs):
+    def end_exp(self, recorder_status: Text = Recorder.STATUS_S, **kwargs):
         """
         End an active experiment.
 
@@ -62,7 +72,7 @@ class ExpManager:
         """
         raise NotImplementedError(f"Please implement the `end_exp` method.")
 
-    def create_exp(self, experiment_name=None):
+    def create_exp(self, experiment_name: Optional[Text] = None):
         """
         Create an experiment.
 
@@ -218,6 +228,30 @@ class ExpManager:
         """
         return self._current_uri or self._default_uri
 
+    def set_uri(self, uri: Optional[Text] = None):
+        """
+        Set the current tracking URI and the corresponding variables.
+
+        Parameters
+        ----------
+        uri  : str
+
+        """
+        if uri is None:
+            logger.info("No tracking URI is provided. Use the default tracking URI.")
+            self._current_uri = self._default_uri
+        else:
+            # Temporarily re-set the current uri as the uri argument.
+            self._current_uri = uri
+        # Customized features for subclasses.
+        self._set_uri()
+
+    def _set_uri(self):
+        """
+        Customized features for subclasses' set_uri function.
+        """
+        raise NotImplementedError(f"Please implement the `_set_uri` method.")
+
     def list_experiments(self):
         """
         List all the existing experiments.
@@ -234,10 +268,14 @@ class MLflowExpManager(ExpManager):
     Use mlflow to implement ExpManager.
     """
 
-    def __init__(self, uri, default_exp_name):
+    def __init__(self, uri: Text, default_exp_name: Optional[Text]):
         super(MLflowExpManager, self).__init__(uri, default_exp_name)
         self._client = None
 
+    def _set_uri(self):
+        self._client = mlflow.tracking.MlflowClient(tracking_uri=self.uri)
+        logger.info('{:}'.format(self._client))
+
     @property
     def client(self):
         # Delay the creation of mlflow client in case of creating `mlruns` folder when importing qlib
@@ -245,13 +283,11 @@ class MLflowExpManager(ExpManager):
             self._client = mlflow.tracking.MlflowClient(tracking_uri=self.uri)
         return self._client
 
-    def start_exp(self, experiment_name=None, recorder_name=None, uri=None):
+    def start_exp(
+        self, experiment_name: Optional[Text] = None, recorder_name: Optional[Text] = None, uri: Optional[Text] = None
+    ):
         # Set the tracking uri
-        if uri is None:
-            logger.info("No tracking URI is provided. Use the default tracking URI.")
-        else:
-            # Temporarily re-set the current uri as the uri argument.
-            self._current_uri = uri
+        self.set_uri(uri)
         # Create experiment
         experiment, _ = self._get_or_create_exp(experiment_name=experiment_name)
         # Set up active experiment
@@ -261,14 +297,14 @@ class MLflowExpManager(ExpManager):
 
         return self.active_experiment
 
-    def end_exp(self, recorder_status: str = Recorder.STATUS_S):
+    def end_exp(self, recorder_status: Text = Recorder.STATUS_S):
         if self.active_experiment is not None:
             self.active_experiment.end(recorder_status)
             self.active_experiment = None
         # When an experiment end, we will release the current uri.
         self._current_uri = None
 
-    def create_exp(self, experiment_name=None):
+    def create_exp(self, experiment_name: Optional[Text] = None):
         assert experiment_name is not None
         # init experiment
         experiment_id = self.client.create_experiment(experiment_name)