Wi-Fi is acronym of Wireless Fidelity， referring to wireless tranmission technology of 8 0 2.11 standard adopted by Institute of Electrical and Electronic Engineers， it also refers to the equipments which meet such standard. Actually， Wi-Fi is a small local area network which has been used to transmit data. As a wireless device， there is a transmitter of Wi-Fi， which， as a matter of fact， will generate electromagetic radiation to its surroudings.

The normal operating power of the most common wireless router is within the range of 30-500 milliwat， smaller than that of cellphone（0.125-2 watt）. Compared with phones， the distance of wireless router， including Wi-Fi equipments， and people is much farther than that of phone and its user， which makes it less possible to be radiated.

The decision made by the World Health Organization about mobile phone radiation is： “ up to now， there is no evidence can prove that cellphones can bring negative influnence towards peoples health. As for the radiation of Wi-Fi， we still have no unambiguouos evidence to prove that it has something to do with any health problems.