The structure and working principle of the oscillating blade-type wave energy power generation device were briefly introduced, and the wave mechanics and the shallow water wave theory were used to theoretically analyze the oscillating blade, then the capture efficiency formula was derived. In order to investigate the performance of the device, the effects of the swing angle and wave height parameters on the hydrodynamic performance of the device was analyzed by using the Fluent simulation software, and the concept of optimal swing angle was proposed, meanwhile, the relationship between the optimum swing angle and wave height was studied. The experimental results showed that, the capture efficiency of the device first increased and then decreased with the increase of the swing angle, and increased with the increase of the wave height. The research provided a theoretical basis for the later device experiments.