The loss and temperature rise of high-power and high-speed permanent magnet motor affect the improvement of power density. Taking a 500 kW, 12 000 r/min high-speed permanent magnet motor as an example, the effects of the selection of pole-pair number, stator winding type, rotor structure and permanent magnet on motor performances, especially on loss, are analyzed. The finite element model of the motor is established, and the rotor structure strength, output performance and loss of the motor are analyzed and calculated. The prototype is trial-produced, and the relevant performances are tested and verified. The results show that the motor has reached a high technical target. It provides some meaningful references for the optimal design of high-speed permanent magnet motor.