Abstract: In order to study the distribution of gas content and gas geological law of 21^-3#coal seam in Dabaoding Mine, based on the theory of gas geology, according to the great coalfield geological exploration information and the lab measurement and analysis data, we analyzed geologic factors of mining gas occurrence, and reached the distribution of mining gas content and gas geological law. The results indicated that the gas content of coal seam was positively correlated with burial depth and thickness of coal seams; the geological structure of coal mine controlled the distribution of gas and tectonic coal, the high gas zones were mainly located in mutation belt of coal seams between the axial parts of anticline and syncline, as well as in cutting belt of coal seams imposed by thrust faults; the degree of coal metamorphism and hydrogeological condition was beneficial to gas preservation in deep areas of the south mine.