diff --git a/vnpy/trader/object.py b/vnpy/trader/object.py
index ab3ef5d7..f9b2e1b8 100644
--- a/vnpy/trader/object.py
+++ b/vnpy/trader/object.py
@@ -6,7 +6,7 @@ from dataclasses import dataclass
 from datetime import datetime
 from logging import INFO
 
-from .constant import Direction, Exchange, Interval, Offset, Status, Product, OptionType
+from .constant import Direction, Exchange, Interval, Offset, Status, Product, OptionType, PriceType
 
 ACTIVE_STATUSES = set([Status.SUBMITTING, Status.NOTTRADED, Status.PARTTRADED])
 
@@ -265,7 +265,7 @@ class OrderRequest:
     symbol: str
     exchange: Exchange
     direction: Direction
-    price_type: str
+    price_type: PriceType
     volume: float
     price: float = 0
     offset: Offset = Offset.NONE