Air spring is a key component in vibration control of air suspension systems in vehicles， and its time-domain dynamic characteristic is an important index to evaluate the vibration isolation performance. To study the time-domain dynamic characteristics of a pipe-type air spring with an auxiliary chamber， a test bench with an air charging system is established to measure the transmitted forces of air spring under harmonic excitations and step excitations. A lumped parameter model for an air spring system is established， and the dynamic complex stiffness model is derived. Based on the convolution theorem， an analytical model for calculating the time-domain dynamic characteristics of air spring is developed. The parameters of the proposed model are identified， and the calculated transmitted force by using the proposed model is compared with the measured data. The results show that the error between estimated values and experimental values is less than 5% under harmonic excitation.