In view of the frequent fracture of the coil spring of the bogie of the metro vehicle in a certain city, a threedimensional model was established by taking the bogie spring of the metro vehicle in this line as the research object. According to the fatigue fracture parts of the spring in the actual project, the force of the spring model under the static strength was analyzed in order to verify the accuracy of the spring model. Based on the measured displacement load data, the load spectrum was established. According to the load spectrum and the S-N curve of the material, the minimum fatigue life of the primary steel spring under different working conditions was calculated. By changing the spring parameters, the minimum fatigue life under different parameters was obtained, and the relationship between the spring parameters and the minimum fatigue life was explored, so as to find out the method to improve the spring fatigue life.