diff --git a/vnpy/trader/object.py b/vnpy/trader/object.py
index 643c1754..06a11eae 100644
--- a/vnpy/trader/object.py
+++ b/vnpy/trader/object.py
@@ -409,6 +409,7 @@ class HistoryRequest:
     start: datetime
     end: datetime = None
     interval: Interval = None
+    interval_num: int = 1
 
     def __post_init__(self):
         """"""