Abstract: In order to study the NOx release characteristics of char under oxygen-enriched atmosphere,the effect of temperature and reaction atmosphere on the release characteristics of NO and NO2 during its combustion was tested by using a constant temperature thermogravimetry-combustion pollutant measurement system. The results showed that the release time was shorten for NOx ,the release rate of NO was increased and the release amount of NO2 was reduced by raising temperature in O2 / CO2 atmosphere. And the results explained and verified by the conversion rate and kinetic parameters of the reaction further. The instantaneous release amount of NO was raised with O2 concentration,and it al- so promoted the oxidation of NO to NO2 ;the addition of water vapor made CO2 and H2 O happen synergistic gasifica- tion,and it made the steam gasification more complex,some water vapor could help to stimulate the release of NO2 and NO;the instantaneous release amount of NO in air was higher than that in O2 / CO2 atmosphere,but the difference of re- lease characteristics of NO2 was a little.