Surface water surveys were carried out seasonally in Lake Poyang from April 2014 to January 2015. Concentrations of nitrous oxide (N₂O) in thirteen sampling sites were measured followed by calculation of N₂O emission fluxes with interface diffusion model. The N₂O concentration in the surface water of Lake Poyang averaged 32.57±17.35 nmol/L with an average saturation of 256.83�Dd#177;129.05%, which implied a state of N₂O-supersaturated. The N₂O flux from water to air was calculated to be 0.83±0.69 μmol/(m²·h) on the average. The highest N₂O flux appeared in spring with an average level of 1.71 μmol/(m²·h), followed by the summer, winter and autumn in a descending order. In spring, N₂O emission rates were significantly higher in the north part of the lake than in the south part. Regression analysis indicated that ammonium in water column had great control effect on N₂O production in summer and winter. About 1.29×10⁷ mol N₂O was emitted from Lake Poyang annually, of which 80.40% emission was in spring and summer. The N₂O-N output of Lake Poyang was estimated in 361.93 t per year, and plays an important role in the N₂O distribution in the Poyang basin.