Abstract: The purpose of the study is to investigate the effects of rice husk-derived biochar and its skeleton on denitrification and N₂O emission. Based on the preparation of biochar skeleton (WBC) and the extract of biochar (BCE) by water-washing method and the enrichment and screening of an anaerobic denitrifier (DB), the microcosm incubation experiment was carried out to explore the removal efficiency of low concentration nitrate (about 10 mg·L^-1) in simulated wastewater by DB. N₂O and N₂O+N₂ emission rates were determined, and the dynamic changes of the physicochemical properties and the nitrate reductase and nitrite reductase activities of the simulated wastewater during incubation were also investigated. Results show that N₂O emission from the simulated wastewater was entirely caused by microbial pathway. The peak of denitrification rate (N₂O+N₂ emission rate, in terms of N) of the treatment DB appeared at 48 h, while that of the treatment DB+BC appeared at 36 h, and that of the treatment DB+WBC even appeared at 24 h. The maximum denitrification rates of DB+BC and DB+WBC (44 087.79 and 46 826.27 ng·h^-1, respectively) were significantly higher than that of DB (38 097.45 ng·h^-1). Compared with DB, the cumulative N₂O+N₂ emissions of DB+BC and DB+WBC increased by 30.17% and 2.86%, respectively, while the cumulative N₂O emissions decreased by 83.04% and 74.52%, respectively, indicating that both BC and WBC increased the denitrification rate and promoted N₂O reduction. Compared with DB+BC, the cumulative N₂O+N₂ emission of DB+WBC decreased by 20.98%, indicating that the denitrification promotion effect of biochar skeleton was not as good as that of biochar, but its conductance structure still played an important role in denitrification.