Abstract: In this paper, dielectric barrier discharge non-equilibrium plasma technology is used to treat lean methane in the exhaust gas of fire flooding. The effects of plasma discharge power (21~46 W), O₂/CH₄ molar ratio (2~10), and gas volume flow rate (400~1200 mL/min) on CH₄ conversion rate, CO₂ and CO selectivity were investigated. The results show that with the increase of discharge power and O₂/CH₄ molar ratio, as well as the decrease of gas flow rate, the conversion rate of CH₄ increases, and the selectivity of CO₂ and CO shows an upward and downward trend, respectively. Under the condition of high discharge power and O₂/CH₄ molar ratio, and low gas flow rate, complete conversion of lean methane can be achieved. The oxidation of lean methane mainly produces CO, followed by CO₂. The selectivity of CO can reach up to 98.89%, while that of CO₂ is about 56.63%.