In order to extract components from the target system effectively and achieve the goal of software reuse, a component extraction method based on design documents was proposed in this paper. Computer aided software engineering tools were used to design the target system, then concept components and system architecture were extracted from this design documents. After the accuracy of extract result was verified by extensible markup language element and matching degree of characteristic element, foundation for software reuse was provided in this way. The application of this method was illustrated through two practical applications: product resource management platform and change-major student system. During this process, concept components of fileUpload and dataDump were extracted and verified, and components which match these concept components were reused successfully for the system. The result shows that the proposed method not only provides a framework of reusable components, but also improves the success rate of software reuse.