In view of the current widely used city intersection signal control system, oriented by the concept of automatic sensor signal control, this paper tries to use a computer's procedural method, with the input of initial conditions, after automatic calculation, a result which will make the vehicles go through the intersection causing the shortest signal control delay time totally will be generated automatically, this article focuses on the automatic selection of phase-sequence designing, and then, there will be a simple example for briefly explanation, which provide reference to design of intersection signal control.