Energy and environment conservation is one of hotspots all around world now. Light emitting diode (LED) road illumination based on Wireless Sensor Network (WSN) technology can not only reduces complexity for arrangement of cables and route construction process, but also show advantage of LED illumination well. Meanwhile, it is good for energy and environment conservation. Route construction is a crucial issue when we use WSN technology. In this paper, we present two network structures, introduce the route construction process of illumination area and derive total transmit power (TTP) of WSN. Then we analyse impact of some factors on normalized TTP and do computer simulation to evaluate them.