This paper presents a switch network based upon averaged switch model to represent the power devices including MOSFET and diode to give a unified approach to modeling of various kinds of converters. The non-ideal features of power devices and circuit components, including turn-on resistor of power devices, DC resistor (DCR) of inductor and equivalent series resistor (ESR) of capacitor, are taken into consideration. As compared to previous approach, the presented switching network can be applied to modeling various kinds of DC/DC converters, including buck, boost, buck-boost, Cuk, Zeta and Sepic, by simply changing two parameters. Simulation results derived from the presented methods are consistent with those derived from SPICE software and thereby validating the presented unified modeling method.