The research dealed with using Wireless Sensor Network(WSN) in the application of tunnel environmental monitoring purpose. First put of this study has concluded in Snow Mt Tunnel for Fire Exam testing.14 nodes have set up during testing.Typical WSN units developed by the research team with about 30 meters communication distance.This stage of study provides the significant data which collected by notebook PC were performed well.Fire dynamic simulator (FDS)software confirmed the monitored information (temperature)，and support the second part of WSN application study.In second part of study，completed WSN are going to be established in Guan Yin Mt Tunnel. Not only temperature MEMS sensor was used，but also CO2/CO were built in the node. In house study has completed，and 53 nodes were produced，and initial set up test has concluded for the ongoing program. WSN system will be installed in the following stage and the completed monitored information will to be expected and performed.