Abstract: Based on the gas geology theory and method, the gas geology law of Sihe Mine was discussed and the analysis was conducted on the geological structu ral features, the effective thickness of the surrounding rock and the overburden strata, hydrological conditions and other factors affected to the gas deposits.The results showed that the geological structure and the effective thickness of the overburden strata would be the major factors to control No.3 seam gas deposit and to cause the abnormal gas emission value from some region.According to all the study results, the gas outburst early warning and gas drainage were conducted in Sihe Mine.The pr ediction of the gas outburst danger was enhanced .An improved monitoring and control system and a gas drainage system was established.The full mine gas drainage「 ate could reach to 73%.