With the development of coal comprehensive mining technology,the strength and frequency of hydraulic support being pressed by the roof plate is continuously enhanced.In order to study the response characteristics of high-pressure and high-flow safety valves when the top plate is pressed,taking the 1 000 L/min safety valve as the base research object,and the model was established respectively by Simulink and AMESim to analyze the influence of the spring stiffness change of the safety valve when the top plate was pressed to the pressure on its response characteristics and the opening and overflow closing time.The results show that the reduction of constant stiffness spring stiffness can effectively reduce the overregulation amount but the oscillation of the valve spool is intensified,and the pressure fluctuation of the safety valve is large;the increase in stiffness can reduce the amplitude of the valve spool and stabilize faster,but the overregulation of the safety valve increases,which is not conducive to unloading and overflow;the variable stiffness spring can effectively reduce the overregulation of the safety valve under the impact load,improve the pressure control accuracy of the safety valve,and thus improve the stability and reliability of the safety valve.In addition,a new structure safety valve with nitrogen as the gas spring was designed.The simulation results show that the overregulation of the nitrogen spring safety valve is 9.5 MPa,the pressure stabilization time is 61.4 ms,the hydraulic cylinder pressure is 35.61 MPa when the safety valve is closed,and the closing delay time is 78 ms,which provides a theoretical basis for the design of the high-pressure and high-flow safety valve.