This paper studies the relationship between the additional confluence of semi-interchange and the ex- isting interchange diversion ramps, presents the full interchange ramp number and calculation formula of combi- nation number for the new off and on ramps and layout and scheme selection points of the adding ramps. In ad- dition, it provides a concrete example of added turning ramps with three-way, four-way and five-way intersec- tion roads. By taking Shenzhuang Interchange in Shanghai as an example, it conducts empirical research.