In order to improve the vibration isolation performance of suspensions, various new structural forms of suspensions have been proposed. In this paper, a quasi-zero stiffness isolator is used in automotive suspensions to form a new suspension-quasi-zero stiffness air suspension(QZSAS).Due to the strong nonlinearity and structural complexity of quasi-zero stiffness suspensions, changes in structural parameters may cause dramatic changes in suspension performance, so it is of practical importance to study the effect of structural parameter uncertainty on the performance of such suspensions. In order to solve this problem, three suspension structural parameters d0,L0,Pc0 are selected as random variables in this paper, and the polynomial chaos expansion(PCE) theory is used to solve the suspension performance parameters such as body acceleration, suspension dynamic deflection, and wheel relative dynamic load response under different excitation. The sensitivity of the performance parameters to different structural parameters was discussed and analysed in the frequency domain. This paper verifies the feasibility of the PCE method for solving the uncertainty problem of complex nonlinear systems, and the research in this paper can provide a reference for the future structural design and optimization of such suspension systems.