Today, CAD/CAM/CAE tools are highly graphical and interactive. But how an interface can be more helpful is not ascertained yet and still interesting to many software workers. From the object-oriented point of view, based on knowledge deducing and event stack structure, we propose a new interface model SRT. Using this model, we have developed an entirely new interaction technique. In this paper, after a review on the development of users interface models and interaction techniques, we will give a detailed definition of SRT, followed by a discussion of what a role it plays in users' design work. Based on SRT model, we developed SDDT, a Software Document Design supporting Tool of ICSDE system. SDDT consists of a concise expert system and a Software Graphic Document edit Too, along with a Software Textual Document edit Tool. SDDT now has been realized on HP workstations, and the new interface of it brought by SRT model has proven to be a very successful interface. In this paper, we will also describe the interface of SDDT.