The anti-collision device of ship berthing and the hydraulic buffer system were provided separately. The working principle of the hydraulic buffer system was detailedly introducted. The system mathematical model was established and the system components parameters were selected. Then the hydraulic buffer system was simulated based on Simulink and the ship displacement velocity and buffer cylinder chamber pressure and flow curves were obtained. Finally, the influence of relief valve pre-compression and the equivalent mass of ship on buffer property were studied. The simulation results show that the relief valve spring pre-compression and ship equivalent mass have great influence on dynamic performance of the system. When the spring pre-compression increases, the ship displacement and buffer time decrease, the buffer cylinder working chamber pressure increases. The spring pre-compression has no influence on flow of the buffer chamber. When the ship equivalent mass increases, the ship displacement and buffer time also increase, the ship equivalent quality has no effect on the maximum pressure and maximum flow on the working chamber of buffer cylinder.