Abstract: ［Objective］ To solve the problems of unstable shell protection performance, complex HD (heat dissipation) system configuration, and low HD efficiency existing in current tram ground charging devices, a scheme of ICHD (internal circulating head dissipation) system for tram ground charging device is designed. ［Method］ The composition and HD principle of the ground charging device are introduced, and the reasons for the low HD efficiency are analyzed. In view of the overall ICHD system of the enclosed cabinet, an ICHD system optimization scheme is proposed. The FLOTHERM simulation software is utilized to compare the airflow velocity and temperature rise between the original and optimized schemes, and experimental verification is conducted. ［Result & Conclusion］ It is found that the overall ICHD system based on air-conditioning cooling is unable to solve the HD issues of high-power and high-heat loss centralized heating devices. This inefficiency is not related to the cooling capacity of the refrigeration system but rather to the airflow circuit of the HD system. The proposed optimization scheme forms a closed-loop airflow circuit between the air-conditioning airflow outlet, inductor and air-conditioning return air vent, significantly reducing the temperature rise of high-power centralized heating devices. This effectively enhances the HD performance of the HD system, resulting in a temperature rise reduction of approximately 20.1% in the inductor of the charging device after optimization. The proposed optimization scheme satisfies the temperature rise requirements of the ICHD system.