Surface water samples were taken during the 25st and 26st CHINARE (Chinese National Antarctic Research Expedition) on cruise tracks in southern Ocean and Prydz Bay during Oct, 2008 and Apr.2009, Oct, 2009 and Apr.2010. The surface seawater N2O concentrations range from 7.4?.1nM to 50.1?.0nM during the 25st and 7.2?.3nM to 17.0?.2nM during the 26st CHINARE respectively. Surface water were generally near equilibrium with atmospheric N2O mixing ratio, with average saturation about 99％ and 90％ during the 25st and 26st respectively. N2O in Surface water turn to be a little more undersaturated southward in both cruises. Highest value found north of 45 during the 25st may result from cyclone introduce divergence, and two other highest value about 50nM were found correlated with low salinity at around 6-12％o in high latitude, which suggests possible effective N2O production by possible unknown mechanism during severely ice melting process. However, no obvious high value found on whole cruise tracks during the 26st CHINARE. The gradually enhance undersaturated southward could possibly due to ice melting process.N2O data obtained during the 25st CHINARE indicate that Prydz Bay water buck were undersaturated with N2O generally, while at station P4-11 in Prydz Bay, extremely high saturation value over 3000％ was found at depth of 75m. The N2O profile were negative correlate with DO, and positive correlates with NO3, however the well known AN20 - AOU linear correlation was not found in Prydz Bay, suggest a possible transportation from other region or different production mechanism in polar marine environment.