Abstract: In order to solve the problem of coal spontaneous combustion, the new gel N₂ foam material was developed. Focus on its configuration scheme, we use the method of compound with two to find out the best compound foaming agent, A1 and A2 by 2∶3 ratio distribution, in the whole experiment process, we strictly follow the principle of single variable, and determine the concentration of the composite foaming agent is 0.95%, the ratio of polymer and water quality is 8.5%, finally synthesize less consumption, high foam expansion, long foam stability time of gel foam. Concentrate foam with compressed gas injection method, we carry on the gel CO₂ foam and N₂ foam stability comparison by airflow method to determine the half-life of foam volume, and evaluate foam stability, finally compress N₂ to produce bubble. It has been applied successfully in the Changhua Coal Mine.