To analyze the performance of leaf spring of tandem suspension of heavy-duty truck, a leaf spring model of multi-body dynamics in tandem suspension for a heavy-duty truck is built with the method of the discrete beam element, and it is a model to solve the problems of the large deformation, non-linear contact and dry friction.The true vertical stiffness change and the hysteresis characteristics of leaf spring can be obtained by adjusting the parameters of the discrete beam in the simulation tests.The characteristic curve of the model can be the same as or similar to the actual leaf spring.The results show that discrete beam method is a better method for describing the real performance of leaf spring of tandem suspension of heavy-duty truck and provide the reliable and convenient leaf spring model for the full vehicle dynamics model.