Abstract: The traditional way in the processing of complete denture has to be manual, low in efficiency and having high rejection rates. Quantitative tooth arrangement can realize perfect quality and high efficiency, applying robot aided processing system and employing computer aided design. A tooth arrangement algorithm has to be developed for such a system that can satisfy the requirements of complete denture preparation and represent the experience of oral restoration experts as accurately as possible. This paper introduces the concept of tooth arrangement method in a robot aided system of complete denture preparation developed by the authors, giving the relevant mathematical model. The results of an application example indicate that this method is logical and efficient.