To improve the efficiency of the tidal energy conversion system, high power density and high efficiency direct-drive permanent magnet synchronous generators are required. Therefore, this paper combines the magnetic-gearing effect with the generator and proposes a novel six-phase vernier generator topology. First, the topology is introduced and the operation principle is described. Second, the paper focuses on the induced voltage optimization by different methods, including parametric optimization, response surface method, and harmonic winding suppression. Also, the induced voltage performance is validated by FEM. Finally, the optimal design is proposed and the conclusions are drawn upon.