Abstract: To explore the influence of suspension system parameters on the vibration performance of the entire vehicle, this paper takes a single-degree-of-freedom variable stiffness suspension system as the research object. By establishing a mechanical model and motion differential equation, the multi-scale method is used to solve the equation and combined with numerical simulation to analyze the influence of parameters such as spring stiffness, suspension damping, excitation frequency, excitation amplitude and initial conditions on the vibration characteristics of the system. The research shows that system parameters directly affect the vibration stability and ride comfort of the entire vehicle by changing the amplitude-frequency characteristics and motion state, providing a theoretical basis for the optimization design of suspension system parameters.