Abstract: In order to effectively prevent the spontaneous combustion of coal and make up for the shortcomings of existing fire-extinguishing materials, a new type of high water-resistant capsule material was developed by adding gluconolactone based on sodium alginate and light calcium carbonate. First, by analyzing the influence of different material content on the molding time and water retention performance of high-water capsules, it is concluded that high-water capsule with a ratio of 2%SA+0.5%PCC+1%GDL has better fluidity and slow molding speed, 2.5%SA+1%PCC+1%GDL high-water capsule has stronger water retention and faster forming speed. Then, the temperature programmed experiment was used to analyze the change of the concentration of the iconic gas during the heating process of the coal sample. The results showed that the CO production of the coal sample with the high water capsule was reduced, and the temperature of the C2H4 gas increased, indicating that the high water capsule has a certain inhibition effect on coal oxidation.