This paper suggests the green proxy software system to keep wireless devices accessible while saving the energy. It is a system that uses a proxy server to build virtual NICs and virtual images for wireless devices in the same WLAN, so that the devices can sleep during idle time while their functionality are pretended to be carried on by the virtual image in the proxy. If a network request is sent to a device, the proxy server will wake up the device. Using this software system does not require any changes to hardware system or network topology; therefore, it has strong flexibility and universal applicability. The green proxy software system is deployed in a test bench with 11 wireless or wired computers, and real-time measurements of energy consumption are provided to sense and record the energy consumption of the system. The results show significant energy reduce that reaches 60% of the total PCs energy consumption. The economic benefit is obvious if the system is widely deployed.