diff --git a/examples/rolling_process_data/workflow.py b/examples/rolling_process_data/workflow.py
index 8581f149b..62523aefd 100644
--- a/examples/rolling_process_data/workflow.py
+++ b/examples/rolling_process_data/workflow.py
@@ -3,8 +3,9 @@
 
 import qlib
 import pickle
-import datetime
 import pandas as pd
+
+from datetime import datetime
 from qlib.config import REG_CN
 from qlib.data.dataset.handler import DataHandlerLP
 from qlib.contrib.data.handler import Alpha158
@@ -14,7 +15,6 @@ from qlib.tests.data import GetData
 class RollingDataWorkflow(object):
 
     MARKET = "csi300"
-
     start_time = "2010-01-01"
     end_time = "2019-12-31" 
     rolling_cnt = 5
@@ -33,9 +33,9 @@ class RollingDataWorkflow(object):
             "class": "Alpha158",
             "module_path": "qlib.contrib.data.handler",
             "kwargs": {
-                "start_time": start_time,
-                "end_time": end_time,
-                "instruments": MARKET,
+                "start_time": self.start_time,
+                "end_time": self.end_time,
+                "instruments": self.MARKET,
             },
         }
         pre_handler = init_instance_by_config(handler_config)
@@ -51,10 +51,13 @@ class RollingDataWorkflow(object):
         self._dump_pre_handler("pre_handler.py")
         pre_handler = self._load_pre_handler("pre_handler.py")
 
-        init_start_time = datetime.datetime(2010,1,1)
-        init_end_time = datetime.datetime(2014,12,31)
-        init_fit_end_time = datetime.datetime(2012,12,31)
-
+        train_start_time = (2010,1,1)
+        train_end_time = (2012,12,31)
+        valid_start_time = (2013,1,1)
+        valid_end_time = (2013,12,31)
+        test_start_time = (2014,1,1)
+        test_end_time = (2014,12,31)
+        
         dataset_config = {
             "class": "DatasetH",
             "module_path": "qlib.data.dataset",
@@ -63,19 +66,19 @@ class RollingDataWorkflow(object):
                     "class": "RollingDataHandler",
                     "module_path": "rolling_handler",
                     "kwargs": {
-                        "start_time": init_start_time,
-                        "end_time": init_start_time,
-                        "fit_start_time": init_fit_start_time,
-                        "fit_end_time": init_fit_end_time,
+                        "start_time": datetime(*train_start_time),
+                        "end_time": datetime(*test_end_time),
+                        "fit_start_time": datetime(*train_start_time),
+                        "fit_end_time": datetime(*train_end_time),
                         "data_loader_kwargs":{
                             "handler_config": pre_handler,
                         }
                     },
                 },
                 "segments": {
-                    "train": (init_start_time, init_fit_end_time),
-                    "valid": (init_start_time, "2013-12-31"),
-                    "test": (init_start_time, init_end_time),
+                    "train": (datetime(*train_start_time), datetime(*train_end_time)),
+                    "valid": (datetime(*valid_start_time), datetime(*valid_end_time)),
+                    "test": (datetime(*test_start_time), datetime(*test_end_time)),
                 },
             },
         }
@@ -86,17 +89,19 @@ class RollingDataWorkflow(object):
             if rolling_offset:
                 dataset.init(
                     handler_kwargs={
-                        "init_type": DataHandlerLP.IT_FIT_IND,
-                        "start_time": "2021-01-19 00:00:00",
-                        "end_time": "2021-01-25 16:00:00",
+                        "init_type": DataHandlerLP.IT_FIT_SEQ,
+                        "start_time": datetime(train_start_time[0] + 1, *train_start_time[1:]),
+                        "end_time": datetime(test_end_time[0] + 1, *test_end_time[1:]),
                     },
                     segment_kwargs={
-                        "train": ("2010-01-01", "2012-12-31"),
-                        "valid": ("2013-01-01", "2013-12-31"),
-                        "test": ("2014-01-01", "2014-12-31"),
+                        "train": (datetime(train_start_time[0] + 1, *train_start_time[1:]), datetime(train_end_time[0], *train_end_time[1:])),
+                        "valid": (datetime(valid_start_time[0] + 1, *valid_start_time[1:]), datetime(valid_end_time[0], *valid_end_time[1:])),
+                        "test": (datetime(test_start_time[0] + 1, *test_start_time[1:]), datetime(test_end_time[0], *test_end_time[1:])),
                     },
                 )
 
+            dtrain, dvalid, dtest  = dataset.prepare(["train", "valid", "test"])
+
 
 if __name__ == "__main__":