Based on the problems of goaf, such as serious air leakage, frequent spontaneous combustion, using foam cement material to reduce or even eliminate the spontaneous combustion of mined-out areas was put forward. Foam cement was made up with cement, blister, flash–setting agent and other materials, which breakthrough the limits of existing fire prevention foam material. Through a series of experiments, characters of foam stabilizing time, mobility density, strength and air leaking stoppage were tested under different proportions of blister and water. According to the experimental results, the fact was obtained that foam cement has minimal air-leakage rate and best effect of air leaking stoppage and the longest foam stabilizing time when the ratio between blister and water is 1:55. Cement samples with different content of flash-setting agent were compounded. By analyzing the cement condensation time under different content of flash-setting agent, it has been found that the content of flash-setting agent were best between 4.6% and 5.0%, which has the shorter condensation time and better condensation effect.