This paper presents a permanent magnet linear vernier (PMLV) machine which is dedicated for low-speed direct-drive applications. Firstly, the machine operation principle is discussed, and the preliminary design approach is formulated. Then, by applying the analytical calculation method for solving the magnetostatic field problem, the machine structure, especially the stator toothed-pole structure which acts on the field modulation function is optimized. Finally, a PMLV machine is prototyped and implemented for direct-drive wave power generation. Both analytical calculation and experimental verification are given to verify its performances.