Reasonable disposal of waste concrete has become an important problem faced by the construction industry and environmental protection departments. In this paper, based on the experimental data of the peeling test of waste concrete mortar, the discrete element method is used to construct the peeling particle model of waste concrete mortar, and the basic parameters are tested. The mortar particle model was crushed in WCFA-VRM400 to obtain recycled aggregate and cement slurry, and the relative error between the simulation data and the real data within a reasonable range. The mortar peeling performance of waste concrete was analyzed by studying the number of grinding rollers, the radius of millstone and the minimum spacing (MS) between grinding roller and millstone. The results show that the peeling performance of concrete mortar decreases with the increase of the grinding speed, the minimum spacing (MS) of the grinding roller and the radius of the millstone. The peeling performance of waste concrete mortar increases first and then decreases within the number of grinding rollers are increased. The calculation model and research results provide reference value for the study of peeling performance of waste concrete mortar.