Abstract: The survey data from Cuimiao coal mine had been researched to identify the importance of geological factors on the coal seam gas content.Based on the relation between the gas content and related factors,the geological structure,coal thickness,coal and surround rock's strength as well as the seam depth,the paper had worked out the priority determinants on seam gas content in the 2₁th seam,the major seam of Cuimiao mine coal.The result shows that the coal seam depth takes the first place to determine the gas content,and the geological structure is followed.