Abstract: The depth of 3302 fully-mechanized caving face is from -1 196 m to -1 135 m in Xingcun Coal Mine, where the earth pressure is large with the risk of rock burst. The earth pressure is big enough to make coal body broken. In order to ensure safe mining, we analyzed the characteristics of spontaneous combustion in goaf, and made project of fire prevention technology by colloid, which took "cooling and controlling oxygen" as the main idea and took "drilling between supports and plugging two ends" as the main measures. It solved spontaneous combustion hidden trouble of face.