[Objective] Aiming at the problem that the relatively high temperature rise caused by high power density affects the power of the motor, this paper takes the high-power-density electric tail rotor motor drive system as the research object and systematically carries out the optimization work on the performance of the motor’s thermal characteristics and heat dissipation structure. The purpose is to improve the heat dissipation efficiency of the motor by modifying the topological structure of the motor’s heat dissipation, and ultimately increase the power density of the motor. [Methods] This study presented a systematic integrated optimization design for system-level heat-dissipation fin coupling. Through computational fluid dynamics simulations of the airflow field surrounding the motor system, the spatial arrangement of heat-dissipation fins-key components of the system was optimized to enhance thermal management performance. Subsequently, nine different heat dissipation topological structures were designed and their efficiency was verified through simulation, resulting in the optimal fin topology. Finally, the accuracy of the research was confirmed by simulating the fluid and temperature fields using the finite element method. [Results] Simulation results demonstrated that when the heat-dissipating metal fins of the motor and the controller housing were arranged alternately at a 50-degree angle, turbulent flow was generated in the airflow field surrounding the housing, effectively enhancing the heat-dissipation performance. The multi-layer square-hole heat-dissipation topology not only offers favorable manufacturability and processability but also achieves high heat-dissipation efficiency. Compared with conventional heat-dissipation fin structures, this innovative design boosted heat-dissipation efficiency by 9.3%. [Conclusion] The systematic thermal management solution proposed in this paper can significantly improve the motor cooling efficiency, accumulating practical experience for the subsequent thermal structure design of aviation motors.