Abstract: To divide spontaneous combustion “three zones” in Sandaogou Coal Mine 5^-2 upper coal seam and study air leakage laws, based on the research of 35106 mining face in Sandaogou Coal Mine, goaf spontaneous combustion “three zones” is divided accurately by investigating the variation of oxygen, carbon monoxide, carbon dioxide concentration during the process of mining face advancing to calculate safety advancing rate. In addition, air leakage velocity can be determined by releasing, collecting, detecting and analyzing sulfur hexafluoride concentration. According to actual situation in this coal mine, effective sealing for air leakage can be utilized to reduce the hazard of residual coal spontaneous combustion.