A novel three-dimensional (3-D) imaging method based on position-shift point array projection is presented. A point-array structure light is projected sequentially onto the reference plane and the object surface, and then, a pair of point-array images form. By analyzing imaging process of the both point-arrays, a mathematical model that is able to express the relationship between height of the object and the lateral displacement of point is established. Based on this model, the 3-D digital image can be calculated by computing the lateral displacement of the same point on the two point-array images. In order to fill up the lost spatial information caused by discrete processing, the point-array can be moved along both lateral and axial direction step by step to achieve high spatial resolution. Experimental results are presented to show the theoretical predictions. This method is qualified for implementing 3-D profilometry of objects with complex topology or large height discontinuities.