Abstract: The fatigue analysis based on the theory of the cracking energy density(CED) is carried out to predict the fatigue life of the air spring. The finite element simulation of the air spring system with an auxiliary chamber is made, and the strain history of each element's center for the air spring capsule is obtained. The strain history obtained by the simulation is substituted into the CED formula to calculate the CED peak of all possible cracking plane for each element's center. The CED peak is used to calculate the related tearing energy's peak. The corresponding equivalent tearing energy is calculated. Finally, the equivalent tearing energy is used to calculate the crack's propagation rate and the corresponding fatigue life of all possible cracking plane for each element's center. Comparing the predicted fatigue's life with experimentally obtained fatigue's life, it is shown that the predicted fatigue's life is 1.91 times of the experimentally obtained fatigue's life, which verifies the reliability of the model and the method of the fatigue simulation.