Abstract: Most of nitrous oxide produced from soil. The flux of N₂O from soil can be resulted from nitrification, denitrification or dissimilatory NO^-₃ reduction to NH⁺₄(DNRA), and nitrification and denitrification are the primary mechanism about N₂O forming. Since aerobic and anaerobic microsites can develop within the same soil, nitrification and denitrification could be occurring at the same time. Their contributions to nitrous oxide emission could differentiate from inhibiting catalysis enzymes and bacteria from each reaction process. Some methods such as ¹⁵N-labelling the substrate, acetylene inhibition and environmental factors inhibition are introduced in detail.