When the pipe system is seen as a fluid network,each node’s transient pressure and flow can be calculated,considering that the process of fluidic transmission and transient transform is studied from the view point of network analysis,which avoids using the method of fluid mechanics.For the maturity of circuit theory,the analysis of circuit diagram and the properties of circuit were used for the expansion chamber mufflers.It is found that using this method,the working state of the attenuator and characteristics can be gotten quickly and intuitively.