This paper presents a traffic light simulation model, which is composed of 6 submodels coded in Arena to help analyze the traffic problem. The model adopts average arrival time and average departure time to simulate the arrival and leaving number of cars on roads. In the experiment, each submodel represents a road that has 3 intersections. The simulation results show that different traffic light duration policies will cause different effects on traffic congestion. Therefore, we can use this model to obtain a good traffic light duration policy for solving the traffic problem.