According to the flight profile of the electric aircraft, the system loss of the motor controller was studied, the thermal resistance network model of the IGBT module was established, and the temperature of the IGBT module of the motor controller was calculated. On the premise of meeting the allowable temperature of motor controller, the cooling structure of IGBT module was improved. The results of MATLAB/Simulink simulation and ground bench test showed that the improved aircooled radiator could meet the cooling requirements of electric aircraft motor controller, and the weight of the aircooled radiator was reduced by 5%.