Hydraulic torque converter is an important part of AT transmission. Its flexible connection characteristics and low-speed torque increase characteristics can significantly improve the adaptability of vehicles to road conditions, avoid engine stall or large speed change, and reduce the impact of transmission shaft components on off-road road. When the mechanical transmission ratio range is determined, the hydraulic torque converter can provide additional transmission ratio when the pump turbine speed ratio is large, and improve the vehicle’s dynamic performance under starting acceleration and low-speed climbing conditions, and greatly improve the vehicle’s acceleration and starting characteristics and climbing ability. In this paper, the modeling of the torque converter in the vehicle dynamics model based on Simulink is analyzed and studied, which lays a foundation for the establishment of the vehicle dynamics model and the adjustment and optimization of the shifting strategy.