3D shape modeling using color light projection is a new and promising technique. It is suitable for fast 3D modeling of moving object, like human head. In this paper, we demonstrated a new method for 3D head modeling by incorporating a priori knowledge of human face and unequal phase stepping to alleviate the color coupling errors raised in color projection scheme. Unlike prior arts, the proposed method utilizes the wrapped phase difference between face and reference directly so that the processing is one-course and time is shortened. An algorithm corresponding to a specific paradigm with R-G-B phase step set to 0-45-180 degree is given. Experimental results demonstrate the effectiveness of the method.