Aiming at the low efficiency of traffic at intersections in urban road networks and the traffic signal control strategy hard to meet changes in upstream traffic flow, a method of intersection traffic signal control and optimization based on timed colored Petri net (TCPN) is presented in this paper. Firstly, the timed colored Petri net models of roads, intersection and signal control system are established, and then an optimization formula for traffic flow with the minimum number of vehicles at the intersection is proposed. Using the number of vehicles on the input and output sections of intersections acquired in 15 phase cycles, the phase timing that satisfies the optimization goal is solved to ensure that the number of output vehicles at the intersection is the largest and the average number of vehicles to be passed on the input road section is the minimum. The simulation results show that the traffic capacity at the intersection is significantly improved, and the average number of vehicles on each output road section increased by 13.3%, 9.7%, 9.8% and 4.3%, respectively.