Abstract: This paper introduces the sealing technology and materials of connection roadway and the current situation of fire preventing and extinguishing technology, expounds the construction of mine airtight chamber in working face connection roadway, the system structure of injecting inert gas airtight in working face connection roadway, the methods of injecting inert gas airtight in closed gas chamber of working face connection roadway, the reseach of fire prevention and extinguishing methods of injecting inert gas airtight in closed gas chamber of working face connection roadway. The practice proves that the system of injecting inert gas airtight in closed gas chamber of working face connection roadway and fire preventing and extinguishing methods have pertinence and validity and reliability.