Abstract: A soil incubation experiment controlled by the acetylene inhibition method wasconducted under laboratory conditions to study the denitrification 1oss and N2O emissions from different nitrogen inputs applied to meadow marsh soil. We designed four nitrogen input level of N0, N1, N2, N3, respectively, the net nitrogen input amount is 0, 1, 2 and 5 mg/g. The results showed that the N₂O average emission rates of N1, N2, N3 were 12.55, 7.59, and 4.04 μg/(kg·h) during the incubation period (23 d). The denitrification loss average rates were 11.52, 9.87, and 3.10 μg/(kg·h), respectively. The average N₂O emission and denitrification loss rates were all significantly higher than the control group (0.09 and 0.10 μg/(kg·h)). This indicated that nitrogen input promoted the N₂O emissionand denitrification loss rates; however, higher nitrogen input (N2, N3) restrained N₂O emission and denitrification loss rates. As nitrogen input increased, the restraining effect increased, and the difference among N1, N2 and N3 reacheda significant level (P<0.05). In the incubation period, carbonmineralization rate increased in 24 h, but decreased at other times as nitrogeninput increased. This indicated that carbon mineralization had a priming effectin the short-term following nitrogen input. In the incubation period, appropriate nitrogen input promoted carbon mineralization, but excessive nitrogen input restrained carbon mineralization.