The particle shape of coarse soil is one of the main influencing factors to determine its macroscopic mechanical properties. To explore the laws of coarse grained soil particle shape on the shear strength characteristics influence, three kinds of coarse granular soils with different particle shape were taken as the research object, the discrete element numerical analysis method was used, with sphericity index for quantitative parameters, we studied the particle shape of coarse grained soil direct shear test stress and displacement in the process of change and the influence of the macro shear strength, and the change rule of shear strength parameters. In addition, the reliability of the revealed law was verified by the laboratory direct shear test. The results showed that with the same normal load, the strain softening phenomenon became more obvious after the shear stress crosses the peak stress with the decrease of sphericity, and the peak stress, displacement and residual strength all increased gradually. With the same sphericity, the peak stress, displacement and residual strength increased regularly with the increase of normal load. The cohesive force and the angle of internal friction increased with the decrease of sphericity. The cohesive force of spherical particle was obviously smaller than that of the other two kinds.