The hydro-pneumatic suspension is widely used in engineering dump truck, the ring seal as an important means to generate friction damping has an important influence on hydrocarbon suspension performance.According to the effect of seal ring damping on the characteristics of hydro-pneumatic suspension, the mathematical model of the single air chamber hydro-pneumatic suspension was established. A two degree of freedom quarter vehicle suspension model was built based on the ADAMS, and the mathematical model of the hydraulic system of hydro pneumatic suspension was built based on AMESim. The analysis model of the whole system was established through uniting the above models and the dynamic characteristics of the system were analyzed by using sinusoidal periodic excitation as input. The test platform was set up to analyze the dynamic characteristics of the suspension. Through the comparison of the analysis results, the parameters in the mathematical model were modified to verify the accuracy of the mathematical model. Comparative analysis of the results shows: when sprung mass of hydro-pneumatic suspension changes, compared with the ordinary model,the maximum values of the body acceleration and wheel relative dynamic load in the built model were significantly reduced, which has improved significantly on vehicle ride comfort and operation safety, through considering the seal friction ring and comparison of simulation and experimental results prove the mathematical model of the hydro pneumatic suspension is more accurate to consider the sealing ring friction, which provides a reference for the design of this kind of system.