Abstract: In order to solve the vibration noise problem of marine motors, a 5.5 kW, 8-pole, 48-slot surface permanent magnet synchronous motor for marine is taken as the object of study, the vibration noise generation mechanism of the motor under the consideration of pole eccentricity is analysed, and the electromagnetic performance of the motor and its electromagnetic vibration noise characteristics are calculated. Based on the theoretical derivation of the influence of pole eccentricity on electromagnetic force, a pole eccentricity structure design is proposed, and its radial air-gap magnetism and harmonic components of electromagnetic force are analyzed by 2D-Fast Fourier Transform, and finite element comparison analysis of the electromagnetic vibration noise of the motor before and after optimization was carried out. The results show that by optimizing the motor structure, the torque pulsation is reduced at rated operating conditions and the electromagnetic vibration noise is effectively reduced from 49.55 to 44.479 dBA, which indicates that the optimization scheme has a good effect on the electromagnetic vibration and noise characteristics of the motor, and finally prototype experiments are performed to verify the validity of the simulation.