Abstract:The simulation models of the pilot-operated check valve and the hydraulic system were built and simulated with analysis by using the AMESim software aimed at the problem of lifting cylinder sliding in raising and pitching system of forging manipulate briefly at stop.The momentary dynamic characteristics of the decompression poppet, the main poppet and the pilot piston of the check valve in system were analyzed.The results show that the pilot-operated check valve cannot close in time is the reason for sliding of the lifting cylinder.In the process of the valve closing, the pilot piston reset slowly, which added resistance to the poppet reset, led to the poppet not reset at once.By increasing reset spring stiffness of the pilot piston made the pilot piston reset quickly, the valve closes immediately, and it can solve the sliding problem efficiently.