In order to find out the bearing capacity and failure mechanism of interface between new grouting-screw pile and soil, the discrete element simulation(DEM) has been used. The DEM model has been built under existing experiment plan of pile-soil interface. According to servo mechanism, the normal pressure on the interface can be unchanged. Then the baseboard is moved at constant velocity, and the relation between shear stress and shear displacement, contact force transport mechanism and the porosity distribution could be obtained when screws of different numbers are adopted. The results show that there is an optimal flutes pitch which can make sure the ultimate shear stress reach to the maximum. And the vaulted failure surface will appear around the pile-soil interface. Moreover, the micro mechanism has a good agreement with indoor experiment.