Abstract: A pot experiment was carried out to explore impacts of application of maize stalk-derived biochar on emissions of nitrous oxide (N₂O), carbon dioxide (CO₂) and methane (CH₄) from and soil physicochemical properties of vegetable fields. Results show that application of the biochar suppressed N₂O emission. Compared to Treatment N (N 400 kg·hm^-2), Treatment NB1(N 400 kg·hm^-2+biochar 20 t·hm^-2) and Treatment NB2(N 400 kg·hm^-2+biochar 40 t·hm^-2) decreased N₂O emission by 76.4% and 70.7%, respectively. But the effect did not increase with increasing application rate of the biochar. Application of the biochar and nitrogen fertilizer promoted CO₂ emission, but did not affect much CH₄ emission. The cumulative CO₂ emission in Treatments NB1 and NB2 was 1.8 times and 2.1 times, respectively, as much as that in Treatment N. Application of the biochar increased soil organic carbon content, which was 15.2% and 21.3% higher, respectively, in Treatments NB1 and NB2 than in Treatment N. Meanwhile, application of the biochar increased the content of ammonium nitrogen and pH, and reduced the content of nitrate nitrogen while maintaining and even increasing yield of the vegetable. Soil pH and content of ammonium nitrogen was 0.265 and 34.9% higher in the field applied with biochar than in the field without application of biochar, while content of nitrate nitrogen was 12.7% lower in the former than in the latter. So biochar has a great potential of decreasing N₂O emission and improving vegetable soil quality. However, it still calls for further study to explore net effect of application of biochar on CO₂ emission and soil organic carbon pool.