A three-dimensional tooth profile measurement system based on projected structured light is presented. The system consists of a CCD (charge coupled device) camera and a DLP (digital light processing) 4500 projection module, combining Gray code and phase shifting fringe projection. A fast and accurate calibration method of camera and projector based on the calibration method proposed by Zhang Zhengyou is presented. Based on the system calibration, dental mold scanning experiments are performed to obtain a three-dimensional point cloud contour of dental wax. The experimental result shows that the system is capable of measuring the three-dimensional dental mold accurately, which provides a basis for the further application in the dental field.