Abstract: Author applied the theory and methods of gas geochemistry to the coalbed gas research in the mine district with low content methane. The coalbed gas is characted by more methane, little heavy hydrocarbon gas and low negative of δ¹³C₁. etc. Author proposed that the concept of mine district with low-content methane is of relativity. In the condition, the coal seams is also of gas disaster. We can judge "activity of coalbed gas" and fore case the disaster-prone of coalbed gas and underground water.