With the development of digital technology, three-dimensional (3D) point cloud data is becoming more and more widely used in oral clinical digital diagnosis and treatment, involving many aspects such as 3D morphological comparison analysis, virtual patient construction, and defect morphological reconstruction. At present, "rigid registration" and "non-rigid registration" technologies have played an important role in the clinical application of oral 3D point cloud data. The similarities and differences between the two technologies and the algorithm principles behind them are worth in-depth discussion and exploration, so that they can better serve the clinical practice and scientific research of stomatology. The author’s team has a certain working basis for the application and research of "rigid registration" and "non-rigid registration" technologies. This article will explain the concepts, algorithm principles and their application in the field of stomatology, and summarize and prospect them to provide reference for the application of oral clinical and scientific research to the two technologies.