In order to investigate the influence of the parameters of the swing-cylinder hydro-pneumatic suspension （HPS） on the “load wheel - suspension - sprung mass” system, a parameter sensitivity analysis on the dynamic response characteristics of the system was conducted under typical working conditions. The mechanical-hydraulic coupled dynamic model was built according to the structural characteristics of the HPS, and then it was verified with the comparison of the results obtained by simulation and experiments from the test rig. The key parameters of the HPS were selected to study their influence on the variation trend of the stiffness and damping characteristics of the suspension, after that their impacts on the dynamic response behavior of the HPS system were investigated under bump excitation. The results show that the stiffness of HPS system is greatly influenced by the initial gas volume of the accumulator when suspension deflection is small，while the position angle of the hydraulic suspension affects most when suspension deflection becomes large at compression travel； the vertical acceleration at the center-of-gravity of the sprung mass and the wheel load are most affected by the initial gas volume of the accumulator at low frequencies and it is most affected by the cross-section area of the damping valve at high frequencies; the suspension deflection is affected by these parameters in a reverse trend.