Abstract: 【Objective】 The research aims to provide theoretical basis for breeding, identification, popularization and application of cold - resistant apple dwarf rootstock. 【Method】The cold tolerance of rootstocks were determined with one-year-old branches of four apple rootstocks including 62-396, BP-176, Y-1 and KM23 with different low temperature treatments. The semi-lethal temperature (LT₅₀) was conducted by using conductance method with Logistic equation, and combined with low temperature freezing injury classification, restoration growth test and field freezing damage investigation. Finally, the cold resistance of apple dwarfing stocks was studied.【Results】Under low temperature stress, the electrolyte leakage rate of branches showed obvious "S" curve, which was negatively correlated with the corresponding low temperature. The semi-lethal temperatures of 62-396, BP-176, Y-1 and KM23 were -42.56, -37.52, -43.79 and -40.77℃, respectively. After low temperature treatment, the sprouting rate of each branch was: Y -1> 62-396 > KM23)> BP-176. 【Conclusion】Depending on the determination results,the cold hardiness of tested apple rootstocks was as the follow:Y-1 ＞ 62-396 ＞ KM23 ＞ BP-176, WHICH can be used as cold resistant dwarfing stock in Yili Valley.