Abstract: With the rapid development and extensive application of CAD technology,design reuse is drawing more and more attention.However,because of lack of effective model representation,most of the existing 3D CAD model retrieval methods can not support design reuse.In this paper,a design reuse oriented design feature model representation is defined and a construction method of the design feature model is proposed.Given an engineering part,the defined design feature model can accurately describe its features with different scales and forms,and the relationships between these features by using extended feature tree,so as to effectively capture the design semantics of the model.Furthermore,the proposed construction method ensures that the model representation has uniqueness and stability by interactively defining the main shape feature and auxiliary features of the model and automatically establishing the relationships between these features.Experimental results show that the proposed representation and construction method of the design feature model can effectively capture the design semantics of the engineering parts,so as to effectively support the search for design reuse.