Abstract: The paper applied the theory of cyclic linear differential automata (CLDA) into the signal timing problem of intersection. A switched service system which was a special CLDA model was set up to describe the length of the vehicles queue. Under a specified condition for the arriving rate and the leaving rate of the vehicles, the model proved that, a given signal timing strategy ‘emptying vehicle and then switching signal' can compel the length of the vehicles queue to vary periodically and form a globally stable queue. Moreover, the cyclic formula of the signal timing was formulated and the best range of cycle was set. The present method was applied to the intersection near the conference center in Haidian district, Beijing. Considering the arriving rate and the leaving rate of the vehicles in the peak time, a signal timing of multiple periods was set up and simulation is completed with the help of the Matlab software.