Abstract: In order to reduce temperature rise of motor coils and controller IGBT, improve heat dissipation performance of the cooling channel for motors and controllers, and ensure that the cooling channel has low flow resistance, this paper takes the cooling channel structure of the driving system of a micro electric vehicle and a motor integrated with a controller as the research objects, and establishes a fluid-structure coupling analysis model of motors and controllers through CFD method. The internal velocity field, flow resistance characteristics, motor winding temperature field and IGBT temperature field under the original structure of the cooling channel are analyzed. The collaborative optimization method is used to intelligently optimize the structural parameters of the cooling channel for the motor and the controller, and seek the cooling channel structure with low flow resistance and efficient cooling performance. The results show that the original structure of the cooling channel has local vortexes and flow dead zones, the flow resistance of the cooling channel t is 31.87 kPa, and the maximum temperature of the motor winding is 120.04 ℃. Under the condition of meeting the goal of an optimization of manufacturing process and flow resistance, a structure with the most significant improvement of winding temperature rise is selected as the final optimization result. After optimization, local vortexes and flow dead zones of the cooling channel are improved, the flow is smoother, and the flow velocity is more uniform. The flow resistance decreases significantly, and the flow resistance decreases by about 12.5 kPa or 39.4% compared with the original model. The maximum temperature at the winding end of the optimized motor reduces by 3.28 ℃ or 2.7%. The research results can provide a theoretical reference for the design and improvement of the cooling structure of motors and controllers for new energy vehicles.