Abstract: In order to control greenhouse gas emission and improve energy production in wastewater treatment plants,a new method based on nitrous oxide(N₂O) oxidizing methane was proposed with an increase in energy production from methane oxidation and a decrease in N₂O emission. This study investigated N₂O production characteristic during endogenous denitrification. The results showed that nitrite and N₂O were accumulated simultaneously when nitrate was used as electron acceptor. Nitrite and N₂O reduction were inhibited when nitrite concentration increased in the range of 13- 90 mg / L,resulting in N₂O accumulation during endogenous denitrification process. Based on these results,to enhance N₂O accumulation by adjusting nitrite concentration was proposed,which could provide the basis of methane oxidation using N₂O sequentially.