Abstract: The reuse of scheme is a difficult problem in the area of product design, because it is difficult for computer to realize the expression of abstract information and the formalization of scheme. After analyzing a lot of semantics elements, the embodiment expression of semantics is realized by fitting the semantics elements together based on the semantics element tables. Then definition of rules of “AND/OR” rules of scheme tree are proposed, at last the formalization of the design process and design result is realized. Because the formalization of scheme not only expresses the result of design but also contains the process information of design, the hierarchical reuse of scheme is realized and the above theory is applied to the system of DDMS(Drawing, design and management system) successfully.