Based on the material thermodynamics and heat treatment commercial simulation software,and taking the actual heat treatment process of the half axle gear of the automobile into account,the effect of deep cryogenic treatment on the deformation of the half axle gear is explored. Taking the 20CrMnTi half axle gear as the research object,by using the DEFORM software,the process of gear carburizing-quenching and deep cryogenic treatment is simulated,by using the JMATPRO software,the material performance database of 20CrMnTi half axle gear is established. The gear deformation information after gear carburizing-quenching and deep cryogenic treatment is obtained. The simulation results show that there is deformation after carburizing-quenching and the radial deformation affects the performance,that is,after the deep cryogenic treatment,the deformation range is reduced,while the radial deformation does not change.