In order to improve the reliability and continuous navigation of ship propulsion, a dieselelectric hybrid field modulation motor with bread-loaf eccentric magnetic poles is proposed in this paper. The permanent magnet of the inner rotor of the motor adopts a bread-loaf eccentric magnetic pole structure and is embedded and fixed on the iron yoke of the inner rotor. The structure can obtain a sinusoidal air gap magnetic field, to reduce the torque ripple of the motor. In this study, some key parameters of the motor are optimized by using the optimization strategy of the combination of genetic algorithm and finite element method. In addition, compared with the conventional magnetic field modulation motor with surface mounted permanent magnet, the motor has a stronger rotor structure. The back-EMF, torque, and loss of the motor are calculated. The proposed motor has good sinusoidal back-EMF, less loss and better stability. Finally, the working modes of the motor in the diesel-electric hybrid ship propulsion system are mainly diesel internal combustion engine driving mode, electric propulsion mode, and hybrid propulsion mode. The system can improve the reliability and continuous navigation of the ship propulsion system.