An apparatus and method for saving power of a USB composite network device is provided. The method includes sending an idle request IRP to a composite driver at a bus driver of a network driver when the composite network device requests selective suspend, sending power state transition information to the composite driver and shifting a power state from a normal state to an intermediate sleep state at the bus driver, and shifting a power state from the normal state to the intermediate sleep state at the composite driver according to the power state transition information, wherein, when the composite network device is shifted to the selective suspend mode, the bus driver and the composite driver are in the intermediate sleep state and an NDIS miniport driver of the network driver is in the normal state.