Abstract: Petri net is a kind of model fit for describing asynchronous and intercurrent phenomenon.Petri net analytic technique can be applied to static structure,as well as to dynamic structure.It is the most suitable for expressing the parallelism and the relativity between events.In the condition of distributed net,for designing the scheme of parallel files transmitting,the traditional method is adopting linear programming method.This method need to calculate enormous linear equation group.Optimized scheme about the parallel files transmitting based on Petri net can shortcut this process greatly,and can obtain intuitionistic and perfect effect.

Key words: Petri net, parallel, files transmit