State space's explosion of Stochastic Petri Nets(SPN) is always one of the important problems to solve.In Stochastic Petri Nets

sequent and parallel transitions are primary structure.Simplification of sequent and parallel transitions can not only help to solve the problem of state space's explosion

but also make preparations for other simplification methods.Meanwhile

in some important SPN models

such as Workflow and Multimedia

there are a lot of sequent and parallel transitions

so simplifying sequent and parallel transition structure

especially deducing its equivalent equation will make a significant contribution to simplification of whole SPN.The authors discuss sequent and parallel transition model and simplification theory

deduce their performance equivalent equations

give an example of simplification of SPN model

and finally analyze the conclusion.