Abstract: The advanced research achievements in the processes of N₂O production and emission，their influencing factors and measurement methods and estimation for total N₂O emision are studied in this paper．The results show that N₂O can be produced by nitrification and denitrification．The soil moisture，soil temperature，pH，soil organic carbon content and soil texture are the main factors that influence N₂O production and emision．According to the measured N₂0 fluxes and some related models，the total N₂O emission from cropland in China is N 398Gg／a，accounting for 10％of the total emlssion from agricultural soil in the world．And N₂O emissions are N 310Gg／a and 88Gg／a from upland and paddy fields，respectively．