To investigate the effects of shear direction on the shear behavior of a soil-structural interface and the shear banding in it, a series of three-dimensional numerical interface shear tests considering various angles of shear direction, defined as the angle between the shear direction and the direction of a surface's roughness anisotropy, are performed using the discrete element method.Simulation results show that (1) shear stress increases with an increasing of the angle of shear direction, with the elastic perfectplasticity observed when the angle of shear direction equals zero; (2) all specimens show bulk dilatancy during the shearing process, increasing with the angle of shear direction; and (3) peak stress increases with the angle of shear direction, as does the thickness of the shear band.