In order to reduce the electromagnetic vibration noise caused by the radial electromagnetic force of permanent magnet synchronous motor,an optimization method based on magnetic bridge offset was proposed based on the finite element analysis method of electromagnetic field,structure field and acoustic field.Taking an interior radial permanent magnet synchronous motor for vehicle as the research object,the position of the magnetic isolation bridge of the motor was shifted to the magnetic pole direction along the circumferential track of the outer diameter of the rotor,and the adjacent distance between the magnetic isolation bridge and the length of the isolation magnetic bridge were optimized.The offset distance of the magnetic bridge was set as 4 mm considering the vibration noise level and the performance of the motor.The radial electromagnetic force,rotor force,motor modal and electromagnetic vibration noise were simulated and analyzed before and after the motor optimization.The results show that the average electromagnetic vibration noise of the motor can be reduced by 16.77% by this optimization method,the noise of the motor can be effectively reduced,but it has little impact on the performance of the motor.The optimization method based on the magnetic bridge offset can improve the motor noise level,which provides some reference for the optimal design of permanent magnet synchronous motor and the suppression of electromagnetic vibration noise for vehicle.