The electromagnetic vibration noise level of a permanent magnet synchronous motor (PMSM) directly affects the Noise, Vibration and Harshness (NVH) performance of an electric vehicle. Taking a permanent magnet synchronous motor (PMSM) for electric vehicle driving as an example, the electromagnetic noise characteristics were studied by combining ANSYS Workbench multi-physical field finite element analysis platform. The electromagnetic vibration force of the stator teeth of the motor is the main source of electromagnetic noise. The magnetic field of the motor can be optimized by changing the slot structure of the motor rotor, so as to improve the electromagnetic vibration force of the stator teeth and reduce the electromagnetic vibration noise of the motor. In order to optimize the magnetic field, three different rotor slot structures are proposed. The most suitable slot structure is found by comparing and analyzing the magnetic field, noise field and electromagnetic force with the structure before optimization. By comparing the results before and after optimization, it can be seen that the optimized motor can effectively reduce the vibration noise of the motor and ensure the electromagnetic performance of the motor.