The requirement of constructing the three-dimensional entity model for oral cavity teeth has been put forward to the research of the orthodontics based on rapid prototyping technology. This paper compares the merits and demerits of the CT scanning and the structured light scanning and finds a method of acquiring the digital model of oral cavity teeth based on the point cloud. Adopt the structured light scanning technology and 3DSS software to acquire the files of the point cloud data, and introduce the files into GeoMagic software. After processing the data files we obtain the high-quality digital model of oral cavity teeth. The optimal scheme and the processing procedure of the point cloud data in GeoMagic software are described in detail in the paper. In addition, we compare the final solid model and the point cloud data and analyses the errors.