The hydro-pneumatic suspension was widely used in engineering vehicle for its excellent nonlinear damping and stiffness characteristics, simple structure and good vibration damping effect. According to the structure characteristic of single chamber hydropneumatic suspension and the characteristics of nonlinear structure parameters, the nonlinear mathematical models of hydro pneumatic suspension are established respectively. The analysis model of the suspension was built based on Simulink. The influences of the cavity area of the suspension cylinder, the initial charge volume of the gas, the area of the damping hole and the effective flow area of the check valve on the performance of the suspension were analyzed. According to the analysis results know that: the area of each cavity of the suspension cylinder and the initial gas filled volume of the gas have great influence on the stiffness characteristics of the hydropneumatic suspension. The effective flow area of the damping hole and the effective flow area of the check valve have mainly great influence on the damping characteristics of the suspension. The influence law of each parameter is different accordinig to working states of the system. The influence law of different structural parameters on the performance of the hydro-pneumatic suspension are analyzed respectively, which provide the reference for the actual research and design.