Optimization the signal timing of the intersections is the key problem of the traffic signal control. For the purpose of reducing the traffic jam, optimization model for the four phases signal control of an isolated intersection is established, in which the total delay of vehicles is adopted as the objective function, and the effective green time in each phase as the control variables. Integer encoded PBIL algorithm and real number encoded EMNA algorithm are proposed to solve the traffic signal timing problem. The experimental results show that both the algorithms can get rational signal timing more effectively with less population size than that of the genetic algorithm.