Permanent magnet assisted synchronous reluctance motor has the advantages of high torque/power density, high efficiency range, high speed, low back electromotive force (EMF), low cost, etc., so it is more and more widely used in new energy fields, especially passenger vehicle drive systems. However, this kind of motor has high salient pole rate, large waveform distortion and large torque ripple, which are easy to generate problems of vibration noise and low efficiency of the motor, resulting in the whole vehicle vibration noise and insufficient battery life. By adding the rotor magnetic isolation holes and changing the direction of the magnetic circuit, the torque ripple at the full speed range of the motor and the total harmonic distortion (THD) content of the corresponding load air gap induced EMF waveform are reduced. The radial electromagnetic force and harmonic response of the motor before and after optimization are compared and analyzed. Finally, the effectiveness of the optimization method is proved by experiments.