For the study of traffic flow, a number of factors for traffic flow is difficult to accurate description variables with specific parameters, but in similar circumstances, traffic flow volume change with approximately in the form of periodic changes, the development of change over time. Therefore, using the method of data fitting the traffic flow is forecast to be a more effective way to. In the article, fit the road resistance and road traffic flow, to accurately determine the parameters of the road resistance and the mathematical expressions of the traffic flow, fitting results are accurate response to changes in traffic flow values. The results facilitate the provision of traffic management on roads in different traffic flow control, to avoid the road congestion in the area. Improve prediction accuracy in the application of the road traffic.