Observation of NO emissions from a field under rice-wheat rotation was performed during the period from November, 2004 to May, 2006 using the static chamber method-chemiluminescence NO analyzer. Characteristics of the emissions and effects of the factors,such as N application, soil temperature, soil moisture and crops on the emissions were analyzed. Results show that in CK (No N applied) and in conventional fertilization (N was applied at rate of N150kg/hm²) the mean NO emission fluxes were (-0.8±2.1)μg m^-2 h^-1 and (5.5±3.3)μg m^-2 h^-1,respectively. N application increased NO emissions flux significantly,and increased more remarkablely in rice season than in wheat seasons because of better soil hydrothermal condition in the rice season. About 56.1% of the total amount of NO emission came from rice season during the total research period, and NO emission in two wheat seasons and fallow season accounted for 32.5% and 11.4% of the total amount, respectively. Due to the high NO emissions come mainly from a few times plough in fallow season after crop harvest, therefore, plough times reduction might reduce NO emissions effectively in fallow season. Soil temperature is the key factor of NO emission flux,and its were linearly regressioned. Soil moisture increase will promoted the NO emission in wheat seasons, while in rice season, soil moisture increase inhibited NO emissions. At the same time, soil hydrothermal condition were reasons of soil NO negative emissions (soil absorption) and the difference contribution of crops participation on NO emissions of between rice season and two wheat seasons.