High pressure water mist fire extinguishing device, also called high pressure water mist gun, is mainly composed of high efficiency four stroke air-cooled engine, high pressure pump set, hose reel, high-pressure hose, and high pressure water mist gun. It has main features of compact structure, simple operation, strong fire extinguishing ability, sustainable fire extinguishing, no pollution to the environment and no harm to human body. It is suitable for large workshop, commercial place, community, subway station, tunnel and construction.