In order to improve the efficiency of traffic flow and reduce the delay of arterial intersections, a coordinated signal control method based on numerical solution is proposed. Firstly, considering the factors such as the shortest green time and saturation of a single intersection, the intersection delay model is established. Secondly, the traffic capacity of the trunk line is improved by optimizing the public cycle and the green ratio of each intersection. Finally, an optimization model with minimum delay as the optimization objective is constructed, and the signal coordination of arterial intersections is realized by taking Yancheng City as an example. The results show that the coordinated control model of adjacent intersections based on the numerical method can reduce the average vehicle delay of two-way vehicles, achieve the purpose of green wave coordinated control of road sections, and improve the road traffic capacity.