Air springs are currently increasingly used for vibration isolation of high-class vehicles and high-speed railways，but the precise model of their dynamic stiffness is not perfect enough. This paper proposes a thermodynamic-based multi-chamber air spring dynamic stiffness theoretical model，which is suitable for the accurate algorithm of passenger car air suspension control. The dynamic stiffness formula comprehensively considers the equivalent damping characteristics generated by the external heat exchange，the air chamber stiffness characteristics of the air bag，and the air bag damping characteristics. Furthermore，the clear physical meanings and precise mathematical expressions of each contribution part are presented. Compared with the traditional air spring model，this model does not restrict the gas change process inside the air chamber，so it has strong universality. The power indicator experiment verifies the accuracy（within 0.5% relative error of the experimental value）and universality of the air spring dynamic stiffness theory proposed in this paper under large strokes，and provides guidance for the theoretical modeling of multi chamber air spring