|The characteristics of man-machine interface for automated CAID system is simulating from the features of design behaviors. This is the basic theory of Intelligent computer systems. Based on this concept, this paper is going to discuss about the ways of building design knowledge into CAID system, and its integration with present CAID systems. The "Intelligen CAID" model is brought up with four basic modules: Data Base for Product Components Geometric Model, Design Knowledge Base, Inference, Engine and Interface. An initial concept about the features in each module based on the design behaviors and its possibility in AI programming is discussed. Based on its functional features and behavior characteristic, a computer graphic environment with Object-oriented Programming capabilities will be the goal for further discussion in the future. A preliminary discussion of its construction tools and methods is presented at the end of this paper.