The interactions between waves and the pendulum wave power converter were simulated, considering Navier-Stokes (N-S) equations as governing equations of the fluid, using the k-ε turbulence model and finite element software ADINA. The setting wave-generating boundary method and viscosity damping region method were developed in the numerical wave tank. Nodal velocities were applied on each layer of the inflow boundary in the setting wave-generating boundary method. The viscosity of the fluid in the damping region was obtained artificially in the viscosity damping region method, and the energy in the fluid was decreased by the viscosity in governing equations. The physical model tests were simulated with the fluid-structure interaction (FSI) numerical model. The numerical results were compared with the experimental data, and then the results were discussed. A reference method is advanced to design the pendulum wave power converter. The method to solve the complex FSI problems is explored.