The development of computer processor has stepped into the era of multi-core, providing a good chance to spread the parallel discrete event simulation. The parallel programming model and synchronization problem during the parallelization of discrete event simulation on multi-core platform were discussed. A parallel discrete event simulator based on multi-core platform was designed and implemented using the optimistic synchronization algorithm. On an HP multi-core server with up to 8 cores, both the overheads of the parallel simulator and the effects of event granularity, process number, lookahead on the simulation performance were tested using the Phold model. The experiment results show that the optimistic parallel discrete event simulation based on multi-core platform could achieve good speedup for simulation applications with coarse-grained events.