According to GB/T 19844-2005, the Chinese national standard of leaf spring, a certain type of leaf spring with gradually changing stiffness was chosen as the research object to compare the superiority of the present modeling and calculation methods of the stiffness of leaf springs. The finite element model and the discrete beam model of the research object were established by using the finite element software Hypermesh and the multi-body dynamics software Adams, respectively. Then, the stiffness of the leaf spring was obtained through simulation. At the same time, the traditional methods of calculating the stiffness of leaf springs through common curvature and concentrated load were also used to calculate the stiffness of the research object, respectively. We compared the simulation stiffness and the calculated stiffness with the test stiffness, and found the stiffness of the discrete beam model is closer to the test stiffness for this leaf spring.