In order to research the capacity differences of road intersections,this paper analyzed the influence factors and calculation models of various types of capacity at intersections and then obtained simplified models through reasonable assumption.2/2,4/2,4/4 intersections at which saturation and forecasted traffic volume were given were taken as examples,and an appropriate type was selected through capacity comparison.This paper can give a predictive estimation of the intersection capacity and provides theoretical data for the type selection of intersections.