Intersection is one of the most important components of urban roads, and traffic flow is the node that realizes route change. When the vehicle passes through the intersection due to the need for traffic flow route conversion, the driver can slow down, change lanes, park, steer. A series of tasks such as acceleration, etc., must be completed, and this process must be completed at the intersection and its neighboring area. Therefore, a number of traffic conflict points are formed at the intersection and its adjacent area, and the intersection between traffic flows in different directions, Traffic conflicts such as merger and direction change occur. Traffic characteristics of intersections are more complex than road sections, and road traffic bottlenecks and traffic accidents are frequent. Good design of intersections ensures safe and efficient operation of the entire road network. Based on the analysis of the serious causes of urban traffic problems, the importance of intersections in improving road traffic capacity, traffic jams and accidents is analyzed. The basic content, types, forms, advantages and disadvantages of intersections are analyzed in detail. Carry out a specific analysis of the crossover design method classified by the crossover point, and demonstrate the existing and unsolved problems.