Abstract: The soil displacement screw piles have been extensively used in the international foundation field. In order to study their mechanical behaviors of augered piling, the discrete element simulations are conducted. The micro-simulation parameters are gained to simulate the behaviors of Fujian standard sand under direct shear condition. Based on the parameters, a ground model is formed in PFC^3D. A comparison between numerical and experimental results shows reasonable agreement. The mechanism of drilling with different penetration rates of auger in different depth soil layers are studied by considering displacement development, stress distribution and the auger resistance development. The numerical results show that the mechanism of borehole depends on penetration rate of auger. Lower penetration rate reduces the disturbed range of the soil around the borehole and vertical resistance of auger. The displacement mode of the soil varies at different depths.