A Wi-Fi has been able to accomplish great transmission due to its co-transfer mode. Each wireless network node has to rely on the way to achieve its mission of information transmission. In unattended sensing network environment, the relay process of how to select an appropriate relay node can adjust power consumption and communication quality, so it has attracted a lot of research attention and considerable results. They are few of researchers in recent years. They applied the fuzzy inference system to the relay selection algorithm, which was confirmed to have a good performance.