The passing data from the electronic police are increasingly used for traffic state identification and signal optimization. Obtaining the specific settings of signal timing is very important for refined traffic analysis. In this paper, traffic signal timing settings are directly calculated from the passing data of electronic police equipment to solve the problem of not being able to obtain signal timing for various reasons in practice. In the experiment, the bidirectional sliding window was used to evaluate the probability of the signal light indication at each time, and the evaluation probability for each time of the sliding range was added up to obtain the overall green probability of the sliding range. The experiment shows that the electronic police data can not only calculate the intersection signal timing effectively, but also eliminates the influence of abnormal vehicles.