An experimental platform was built to investigate how aqueous foam extinguishes fire in the upper area of a goaf. A temperature-programmed oxidation testing method was used to illustrate the inhibitory effect of foam. The results showed that foam has good accumulation characteristics, cooling performance, blocking effect, and inhibition. Foam extinguishes the fire in the upper area of a goaf and cools the entire goaf from bottom to top; it even diffuses into the interior of the high-temperature zone and extinguishes any hidden fire in the porous medium. In addition, foam blocks all the cracks in the goaf, thus blocking the air supply and maintaining a constant negative pressure in the goaf. By restricting chemical reactions between coal and oxygen, foam increases the crossing point temperature and reduces CO generation and thus prevents the further oxidation of coal. (C) 2016 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.