To achieve the refinement of urban traffic signal coordination control, the selection of coordinated object should not just focus on the subarea, but needs to be further refined to the attachments of direction paths. In this paper, first, a concept system reflecting the directional demand of coordination control was established by defining the coordination path, the coordination path chain and the coordination path set, as well as the parent path and sub path which constitute the path chain. Then, the counting method of path chains was analyzed. Moreover, according to the trajectory distribution of vehicles in the road network, the corresponding optimization rules and processes of coordination path set were established from the perspective of the intersections number (namely the length of the path chain) and the traffic flow carried by the path chain. The results of example analysis show that the proposed method can select the main path chains with large flow in the control area according to the number of intersections to be coordinated and the flow of traffic path, which can further enrich the division theory of control sub area and intersection group.