Coal mine fires pose a threat to the lives of underground workers and cause incalculable losses to the national economy. When a fire occurs, the temperature in the underground wells will rise, which becomes a huge hidden danger that needs to be controlled to prevent disasters. In this paper, using sodium carboxymethyl cellulose as a matrix and through graft copolymerization of acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid, a novel fire-extinguishing gel with high water absorption and high resistance has been prepared. It has a high water absorption ratio as well as an excellent fire prevention effect. The microscopic reaction and structure of the product are analyzed by infrared spectroscopy, thermogravimetry, X-ray diffraction and scanning electron microscopy. By testing the properties of the gel, it is proven that the product has a fast water absorption rate with a high ratio, strong salt tolerance, good water retention and the obvious effects of filling, sealing and fire extinguishing. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.