Abstract: There are three external factors limiting the safe wintering of winter wheat, which are the degree of cold-acclimation, the temperature of wintering period and the temperature of returning green stage. In order to understand the impact of cold-acclimation on cold resistance of winter wheat, 2 varieties with different cold resistance were used as materials, de-acclimation and low-temperature treatment were conducted in the lowtemperature acclimation stage, the plants survival rate and antioxidant enzymes activities were examined. The results showed that the injury degree of plant with two days of 10℃ de-acclimation treatment was significantly lower than that of 20℃. The survival rate of cold resistance variety (DM1) dropped significantly only with two days of 10℃ de-acclimation on November 10, while the survival rate of cold sensitive variety was 50% with two days of 10℃ de-acclimation on October 26. After October 31, the survival rate of cold resistance variety was less than 50% with two days of 20℃ de- acclimation and then three days of - 12℃ . Under the same treatment, the survival rate of cold- sensitive variety was less than 50% during all the stages. The highest activity of SOD enzyme in cold resistance variety was obtained with two days of 20℃ de-acclimation and then one day of - 12℃ . The survival rate of winter wheat was decreased by cold de- acclimation during coldacclimation period.