Establishing a reasonable air spring dynamic model for medium?low speed maglev vehicle is a necessary condition for the prediction of its dynamic performance. Based on the basic principles of vibration mechanics and elasticity mechanics， a nonlinear dynamic model of medium?low speed maglev vehicle air spring system was established. The system parameters were identified according to the test results， and the accuracy of the model was verified by experiments. The difference between the linear model and the nonlinear model was compared based on the dynamic test results of the line. The results show that the relationship between vertical load， internal pressure and displacement is a cubic function within the range of ±70 mm effective stroke， and the relationship between load and displacement is linear when the effective stroke is larger than 70 mm. The lateral stiffness of maglev vehicle air spring is very large and can be approximated by piecewise linear method. When the vehicle speed of straight line is greater than 30km/h and the radius of curve line is less than 100 m， the deviation of linear model calculation results is large， the calculation accuracy of nonlinear model is significantly higher than equivalent linear model. The research results can provide theoretical basis for the design and dynamic performance prediction of medium? low speed maglev vehicles.