The diagrams of damping valve with annular slice and hydro-pneumatic spring are given. According to the calculation method of the sectional linear speed characteristic, the damping coefficients and the resistance values at the valve open point and the maximal valve open point are deduced. Based on the principles of sheet deformation and aperture throttle, the function relation between flow and pressure difference in turbulent state is researched before and after the damping valve is open. After that, the system elastic force value is deduced by using equation of state of real gas. The correctness of the design method is validated by means of the comparison between performance test and simulation data. Eventually, the influence rules of different parameters of damping valve on the speed characteristic of hydro-pneumatic spring are analyzed so as to provide reference to the research on the internal characteristic of damping equipment.