Abstract: For assuring safety of large sized, fuel-loaded passenger airplanes entering hangar and being under maintenance and repair work, the first applicat- ion of high expansion foam extinquishant was in our hangar.After 3 year's several ground fire extinquishing operations and test spray; the results of this research has reached the same level with similar type fo-reign technical standard.After 5 minutes fire extinquishant spraying, the whole hangar surface area will be covered with foam, piling higher than 10 meters submerging the whole airplane.extinquishing the fire,thus protecting the airplane and hangar.will further development of this research,we established our high expan-sion foam fire extinquishant criterion,so as toextend the application of this new technique into mining,steel work,petroleum and chemical industry and fire extinquishing department.