Abstract: Knowledge reuse of product design has attracted increasingly extensive attentions from enterprise and academic field domestically and abroad. Design knowledge reuse is required by small and medium-sized enterprises in china. According to this requirement, this paper discusses several pathways and approaches to implement product design reuse, mainly including the strategies of mass customization for design, commercial software-based reuse, and Web-based parts library for resource sharing, and product knowledge reuse based on CAD knowledge and engineering semantics. The reported approach is a double network based on CAD knowledge and engineering semantics. The purpose is to solve lower product structure-based reuse problems, involving knowledge representation and retrieval.