Abstract: In the field of new energy vehicles, IGBT module is responsible for controlling motor drive and battery charging. Under high load conditions, heat accumulates rapidly. If the heat dissipation is not good, the module will overheat and fail, reducing the safety and durability of the vehicle. In order to improve the heat dissipation performance of the IGBT module, the structure of the heat dissipation substrate of the IGBT module of Infineon Company was innovatively optimized. The Pin needle on the back of the heat dissipation substrate of Infineon Company was changed from the in-line layout to the staggered layout. The density spacing was reduced from 2.5mm to 2mm, and three straight guide plates were added in the middle of the substrate. Firstly, SOLIDWORKS 2025 software is used to build a three-dimensional model of IGBT module and heat dissipation substrate. Secondly, ANSYS software Fluent module is used to simulate and analyze the fluid-solid coupling heat transfer calculation model of computational fluid dynamics ( CFD ). The simulation results show that before optimization, the maximum temperature of IGBT chip is 102 °C, the minimum temperature is 71.7 °C, and the outlet flow rate is 0.35 m / s. After optimization, the maximum temperature of IGBT chip is 98.6 °C, the minimum temperature is 69.6 °C, and the outlet flow rate is 0.72 m / s. Compared before and after optimization, the maximum temperature of IGBT chip decreased by 3.4 °C, the minimum temperature decreased by 2.1 °C, the temperature difference decreased by 1.3 °C, and the average flow rate and coverage of coolant in the flow channel increased. It is beneficial to the cooling of IGBT chip and the safety and stability of IGBT module.