Abstract: The potential of ultra-low concentration gas is pointed out through the analysis of energy contained in ultra-low concentration gas drained from coal mine. This paper introduces the recovery and utilization of methane below 7% of the exhausted methane concentration in Dingji Coal Mine. The gas concentration is reduced to 1.2% after mixing with air. It is fed into regenerative thermal oxidizer for gas oxidation, generating high-temperature flue gas above 900℃, and generating medium-temperature and medium-pressure steam for power generation and heating of back-pressure steam turbine through flue gas waste heat boiler. This paper describes the method to solve the problem of safe transportation of concentrated gas by using the technology of secondary mixing transportation of low-concentration gas, describes the method to improve the thermal efficiency of regenerative thermal oxidizer furnace by using the technology of low-temperature hot air reuse of gas oxidation, and describes the application of combined heat and power technology of back-pressure turbine and post turbine to solve the problem of stable operation of units adapting to great fluctuation of thermal load in Dingji Coal Mine. The economic and social benefits of oxidation and utilization of ultra-low concentration gas in Dingji Coal Mine are analyzed.