To improve the efficiency of wave power generation technology, a mathematical model of the system from wave input to motor output was established. The key parameters that affected the system′s power generation capacity were analyzed by using theoretical modeling and simulating, so as to provide theoretical guidance for the research of the constant speed control strategy of the hydraulic energy conversion system. The hydraulic energy storage system of wave energy generation was composed of 3 parts. The mathematical model of the system was established by analyzing each component′s motion equation and energy equation, and finding the connection parameters between the two components. The key parameters and characteristics of the system were determined qualitatively by analyzing the system′s power equation. To confirm the accuracy of theoretical analysis, the AMEsim simulation platform was used to design and imitate the system. The results showed that the motor′s output power was affected by the height of the wave, period, flow area of the proportional flow valve and the motor displacement. The highest order of the influence was 1, 4, 4 and 2, respectively. The results also verified that the precharging pressure of the accumulator had little influence on the motor′s output power.