The water valve with the leading discharged valve under high pressure and large flux of a large hydraulic press was researched as an object. The structure and principle of high pressure and large flow water valve was analyzed, its dynamic mathematical model of the mechanism was established, and the problem of opening and closing movement response time of the valve was researched systematically. The influence law of the operation water pressure, system gain and cam wear on the valve opening and closing movement response time were analyzed. By using the Matlab/Simulink numerical simulation software to analysis the model, the interrelations between the water valve’〖KG-*2〗s response time and the system gain, the system pressure and cam wear were obtained. The simulation results show that the water valve has a transient nature in response, and the faster the main valve is opened, the more obvious is the transient nature. Under the same water pressure, as the gain increased, the response of the main valve becomes faster. The simulation results prove the effectiveness of this research, the opening and closing movement time of the valve directly affects the performance of hydraulic machine operation, so the opening and closing time lag of the valve is the main cause of the drive system malfunction. The research results provide references to the optimization for opening and closing of the water valve, the hydraulic machine fault diagnosis, proper use and maintenance of hydraulic press. 