A DEM numerical model is constructed for analysis of ultimate lateral resistance to piles in sand. The pile was modeled as a rigid body with two kinds of pile movements: rotational and translational movement, simulating free head and fixed head condition, respectively. In the numerical experiments, the lateral resistance, lateral pressure distribution along the pile and the displacement of pile at different depths can be measured and used to construct p-y curve. In addition, the soil-pile interaction can be examined in detail to reveal the extent of influence due to the movement of the pile. In general, the results of the numerical simulation were compared favorably with other semi-empirical solutions.