In order to suppress the cogging torque of permanent magnet synchronous motor and reduce the vibration and noise of motor, a structure of stator tooth jacking auxiliary slot and rotor outer circle eccentricity is proposed to suppress the cogging torque and improve the output performance of motor. The analytical formula of the distribution function of the stator tooth top before and after slotting and the main air gap is established. The relationship between the stator slotting and the main magnetic field distribution and the cogging torque of the motor is analyzed. At the same time, the influence of the rotor outer circle eccentricity on the cogging torque is analyzed. Taking the built-in 3-phase 8-pole 48 slot V-type permanent magnet synchronous motor as an example, the number of auxiliary slots on the stator tooth top, slot width, slot depth, slot spacing and rotor outer circle eccentricity are optimized and compared by using the finite element method, and the optimal parameter matching is obtained. The results show that the double rectangular symmetrical slotting on the stator tooth top and the eccentricity of the rotor outer circle can effectively improve the magnetic field distribution of the main air gap and restrain the cogging torque of the motor. The harmonic amplitude of the optimized air gap magnetic density 5, 11, 15 and 17 decreases significantly, the peak value of the cogging torque of the motor decreases by 59.6%, the sine of the back EMF waveform increases, the average torque increases, and the output performance of the motor is significantly improved.