We analyzed the N₂O content of surface seawater sampled from Prydz Bay, Antarctica, on a cruise track between 30°S and 30°N during the twenty-second Chinese National Antarctic Research Expedition during austral summer, 2006. The surface water showed an average pN₂O value of 311.9±7.6 nL·L^-1 (14.1±0.4 nmol·L^-1), which was slightly undersaturated. The air-sea N₂O flux in the region was -0.3±0.8 μmol·m^-2·d^-1; however, N₂O in the surface water was oversaturated in most stations along the cruise track. Saturation anomalies were greater than 10%, with a maximum of 54.7% being observed at the Equator, followed by 31% at 10°N in the Sulu Sea. The air-sea fluxes at these locations were 12.4 and 4 μmol·m^-2·d^-1, respectively. Overall, the results indicated that surface water in Prydz Bay was near equilibrium with atmospheric N₂O, and that ocean waters in lower latitudes acted as a N₂O source. Physical processes such as stratification, ice-melt water dilution, and solar radiation dominate the factors leading to N₂O saturation of surface water of Prydz Bay, while biological production and upwelling are primarily responsible for the N₂O oversaturation of surface water observed in subtropical and tropical regions along the cruise track.