Abstract: A portable WiFi sensor based on the ultra-low power consumption controller MSP430F149 is designed for the acquisition，processing，storage，and management of various toxic and hazardous gases concentration.The switch and general base station，with optical fiber as the transmission media，is used to establish a WiFi sensor network.This network is capable of realizing transmission and conversion of data acquired by this portable WiFi sensor between WSN and the Internet，providing a solid solution for online monitoring of ventilation environment for the stope and the tunnel especially for both the tunnel face and single end tunnel.Its application can effectively avoid accidents due to blindly operation when necessary parameter concerning the environment is scarce.This network has been applied in certain metal mine and produced satisfactory effects in ensuring safe production and expanding economic interests.Therefore，this network is supposed to be applied and promoted.

Key words: Mine ventilation, Online monitoring, Wireless sensor network, Portable WiFi sensor