Abstract: Abstract：In view of the unsatisfactory nitrate nitrogen removal and high N₂O emission in the deep treatment of sewage plant tail water in artificial wetland, we designed and constructed the artificial wetland of CWs1 pure gravel, CWs2 gravel+3% iron carbon, CWs3 gravel+8% iron carbon as a small pilot plant, and investigated the influence of iron carbon material on nitrate nitrogen removal, N₂O emission reduction and microbial community in the artificial wetland, and the results showed that: the artificial wetland by adding the iron carbon The results show that the artificial wetland with iron carbon filler has significant effect on nitrate nitrogen removal and very obvious effect on N₂O emission reduction. Under the condition of 18 mg/L nitrate nitrogen in influent water, the nitrate nitrogen concentration in effluent water of CWs2 and CWs3 can be reduced to below 0.5 mg/L, and the removal rate reaches more than 97%; the N₂O emissions of CWs2 and CWs3 are 629.857 μg/(m²·h) and 576.486 μg/(m²·h), and the emission reduction rate reaches 52.72% and 56.52%, respectively; after the addition of iron-carbon filler, the system has a significant effect on denitrification and organic matter degradation, and the microbial community is also affected. denitrification and organic matter degradation were screened and optimized.