The research is a sub-project of the National Key Technology R&D Program in the 11th Five year Plan of China, which focues at the development of the Computer-aided industrial design system for the CNC Machine Tools. Based on the research of the design task model, the paper explores the process of the development of the computer aided industrial design system, and presents the development of the DTM-CAID system (Computer aided Industrial Design System based on Design Task Model)In this thesis, the design task model is built to connect product design process and the business logic model of the system. And it plans the software development process and implementation details. Besides, the thesis creatively classifies the use cases tool to assist the different phases of the software development. Different forms of use case tend to be useful for different purposes. In the analysis phase, it helps the designers to get the user’s needs; In the construction phase, it helps the designers to find out the various interaction between the actors and the functional modules; in the system implementation phase, it helps to guide the interface design, interaction design and software programming; in the system test phase, we can test the use cases.This thesis starts from building the product design task model, explores the process and methods of the system development. Then, based on the cooperation with NC companies and the user needs experiments, this paper focus on the content of CNC Machine Tools’design task and use cases modeling, and ultimately realizes the system via current computer techniques. This kind of implementary mechanism can provide an effective solution towards other CAID systems.