diff --git a/vnpy/pricing/crr.py b/vnpy/pricing/crr.py
index ca7fabcd..25253220 100644
--- a/vnpy/pricing/crr.py
+++ b/vnpy/pricing/crr.py
@@ -26,8 +26,6 @@ theta：当t变动1天时，price的变动（国内交易日每年240天）
 vega：当v涨跌1个点时，price的变动（如从16%涨到17%）
 '''
 
-from __future__ import division
-
 import numpy as np
 from math import (isnan, exp, sqrt, pow)
 
@@ -180,4 +178,4 @@ def calculateImpv(price, f, k, r, t, cp, n=15):
     # 保留4位小数
     v = round(v, 4)
     
-    return v
\ No newline at end of file
+    return v