Abstract: Fuzzy logic presented in the paper simulates the control logic of signal controller at oversaturated in- tersection during peak time.Fuzzy logic rules of green time extension value are given based on the vehicle queue length.The available green time of each approach is decided according to statistical average queue length and the fuzzy logic rules.The fuzzy logic control optimization effect was compared with the effect of tradition- al optimization method by Sim Traffic simulation.The peak hour traffic flow field data of Ping Le Yuan inter- section in Beijing city is observed.Based on the delay statistics,the optimization method using fuzzy logic pro- duced preferable improvement over traditional timing method.This method has the popularizing market.