Based on 1T15M-2 type air spring, the experiment system of air spring with auxiliary chamber was established. The influential factors on dynamic stiffness of air spring with auxiliary chamber were studied by experimental methods, and the influential laws were described in detail, at the same time the influential mechanism of factors on dynamic stiffness was discussed. Experiment results showed that, vibration frequency, vibration amplitude, pressure of air spring, orifice open and volume of auxiliary chamber are the main factors on dynamic stiffness of air spring with auxiliary chamber. With the increasing of air pressure in air spring and vibration amplitude , the dynamic stiffness of air spring would increase. And increasing the orifice open and volume of auxiliary chamber both cause the decreasing of dynamic stiffness of air spring, but when the volume of auxiliary chamber is 2 times more than that of air spring , change of auxiliary chamber volume have little influence on dynamic stiffness of air spring.