Abstract: In order to study the compaction characteristics of gangue during the pushing process of compaction mechanism, the particle shape model of gangue is established.The contact parameters of gangue are obtained by measuring the rest angle.The influence of particle size distribution on the compaction characteristics of gangue is studied by the combined means of the laboratory test and discrete element method.The results show that the continuous gradation with Talbol coefficient n=0.4 is the optimum size gradation of gangue and has compression ratio, and the compactness of gangue is obviously increased when the compressive strength is 3 MPa, which is the optimum compressive strength.EDEM is suitable for finding the optimal particle size distribution of gangue filling in a mine quickly and effectively, which provides a reference for the stope application of gangue filling.