To explore the dynamic stiffness characteristics of air spring, based on the CFD and the fluid-structure coupling method, the finite element solid model of the air spring with an auxiliary chamber was constructed in the ABAQUS, and internal gas part of the air spring was established in STAR-CCM+, and data timely exchange by SIMULIA between ABAQUS and STAR-CCM +, and eventually the dynamic stiffness of the air spring was obtained. The study results show that: when the excitation frequency change from 1 Hz to 10 Hz, dynamic stiffness of the air spring vary markedly; at the same frequency, the greater the load pressure is, the greater the air spring dynamic stiffness is; the greater the excitation amplitude is, the greater the dynamic stiffness of air spring is; the amplitude of vibration has great influences on the dynamic stiffness of air spring.