Abstract: Traffic signal optimization is based on the dynamic fluctuation of traffic flow,which is a best way to decrease traffic delay and increase traffic efficiency. In order to cost less time during optimization simulation, we presented a kind of parallel traffic signal numerical algorithm. hhis algorithm first defines the time intervals of traffic signal timings from the experience of traffic engineering experts and managers, then lists the feasible groups of time setting with the given interval p,and dismisses each plan to according computing node. After the node finishes its simulation task, the main node will accumulate the simulation report. The simulation with Paramics shows that, with our four computing nodes in the parallel network, the speedup ratio is 1. 75，and the simulation is greatly improved, also the optimal plan is selected quickly.

Key words: ITS, Traffic simulation, Parallel simulation, Paramics simulation system