Abstract: The relationships between mortality rate and low temperature for different cultivars of winterspring wheat during midwinter period were identified through twoyear outdoor potting experiments and indoor manually controlled freezing experiments. We defined the lethally critical temperature and the density of antifreeze capability when the mortality rate reached 10%, 20% and 50% for different cultivars of winterspring wheat during midwinter period.  The strongwinterness wheat (Yanda 1817 and Jing 411) showed the best freezing resistance and the 50%lethal temperatures (LT₅₀) of these two cultivars were -21.5 ℃ and -21.2 ℃, respectively. The freezing resistance of winterness wheat and weakwinternes wheat were worse than that of strongwinterness wheat. The LT_50 of winterness wheat cultivars Nongda 211 and Nongda 5363 were -21.1 ℃ and -20.3 ℃, while that of weakwinterness wheat cultivars Zheng 366 and Ping’an 8 were -18.5 ℃ and -18.4 ℃, respectively. Springness wheat (Zheng 9023 and Yanzhan 4110) showed the worst freezing resistance, and the LT₅₀ were -15.4 ℃ and -14.7 ℃, respectively. When temperature declined to freezing injury occurred, mortality rate increment for weakwinterness wheat was the highest for each 1 ℃ decrease. The mortality rates of weakwinterness wheat cultivars Zheng 366 and Ping’an 8 increased by 16.8% and 25.8%, and that of winterness wheat cultivars Nongda 211 and Nongda 5363 increased by 14.7% and 18.9%. The mortality rate of strongwinterness wheat cultivars Yanda 1817 and Jing 411 increased by 15.4% and 13.1%, and that of springness wheat cultivars Zheng 9023 and Yanzhan 4110 increased by 13.8% and 15.1%. Comparatively, if temperature decreased continuously after the occurrence of freezing injury, the weakwinterness wheat would suffer greater risk.