The stability of output power of wave power generation system can be achieved by wave power converter with pressure-maintaining storage methods based on hydraulic transmission system. The adoption of dual-stroke inverse pendulum wave power converter can improve the energy utilization rate. A mathematical model for this generation system is given， and a computer simulation is conducted by MATLAB/Simulink software. Moreover a semi-physical simulation is done in a semi-physical simulation platform. The computer and physical mode simulation results show that the output power of the system is stable under the action of accumulators and the control system， which validates the feasibility of the proposed generation system.