Characteristics of greenhouse gas emission had became the focus of global change study under the background of climate warming, and the wetland ecosystem and greenhouse gas emissions are closely related. Understanding the effect of water change on the dynamics of wetland N_2O emissions is important for the scientific management of alpine wetland in arid area.Taking the alpine wetland at Swan Lake of Bayinbuluke in the middle Tianshan Mountain as a study area, the emission characteristics of N_2O was measured under different water conditions at alpine wetland ecosystems using the method of static steel chambers and gas chromatography. Results showed that: (1) The average daily emissions of N_2O at perennial seeper area, seasonal water area and perennial dry area were 1.27, 0.99, and 0.98 mug·m~(-2)·h~(-1), respectively, while the cumulative daily emissions of N_2O at perennial seeper area, seasonal water area and perennial dry area were 30.61, 23.97 and 23.08 mug·m~(-2), respectively. (2) The curve of N_2O daily emissions in seasonal water area had three peaks, which occurred at 2:00 (1.30 mug·m~(-2)·h~(-1)), 11:00 (1.28 mug·m~(-2)·h~(-1)), and 21:00 (1.66 mug·m~(-2)·h~(-1)), while the curve of N_2O daily emissions in perennial dry area peaked at 9:00 (1.40 mug·m~(-2)·h~(-1)) and 17:00 (1.42 mug·m~(-2)·h~(-1)). (3) Environmental factors had significant effect on N_2O emissions in wetland ecosystems. There is a significant positive correlation between the soil N_2O cumulative emissions and vegetation living biomass at all areas. The significant correlation between N_2O emissions and soil temperature of underground 10 cm was only found at perennial seeper area (P=0.018), while the correlation between N_2O emissions and soil water content was significant (P=0.043) only at seasonal water area.