To investigate the response of N₂O emission to the gradually elevated CO₂ concentration and the reduction of nitrogen addition in wheat fields, we conducted field experiments using Yangmai 22 as the experimental material. The experiments were carried out on a field equipped with an open-top gas chamber, forming an automatic CO₂ concentration control platform. This setup allowed us to carefully monitor and control the CO₂ levels throughout the experiment. A gradually elevated CO₂ concentration (EC, an increase of 40 μmol.mol^_-1 year by year from 2016-2017 wheat growing season until 120 μmol.mol^_-1 in 2018-2019 growing season) was set up, compared to the ambient atmospheric CO₂ concentration (AC). The amount of nitrogen fertilizer were set as the conventional nitrogen addition (N₁, 25 g.m_-2^{) and the reduction treatment (N}₂, 15 g.m_-2^). The sampling and flux determination of N₂O were carried out by static camera obscura gas chromatography in wheat field. The results indicated that throughout the winter wheat growing period, the trend of N₂O emission under different CO₂ concentration and nitrogen fertilizer treatment was consistent, and the overall trend showed a fluctuating decline. The impact of gradually elevated CO₂ concentration on N₂O emission was found to be not significant during the winter wheat growing season. The nitrogen reduction treatment has shown effective in reducing N₂O emission in wheat fields, resulting in a significant reduction of cumulative N₂O emission by 45.2% (p=0.004) under atmospheric CO₂ concentration. The impact of nitrogen reduction treatment on N₂O emission was evident in winter wheat from the booting to milking stage. Under the combined effect of gradually elevated CO₂ concentration and reduction of nitrogen fertilizer addition, nitrogen addition is the main factor affecting N₂O emission in wheat fields.