Nitrous oxide (N₂O) is one of the most important greenhouse gases emitted from the fertilized agricultural soils. This agricultural greenhouse gas is produced through nitrification and denitrification processes. The possible factors affecting N₂O emissions have been widely studied, including the timing and rate of irrigation and nitrogenous fertilizer application, and environmental soil conditions such as temperature, moisture content, and microbial activity. The response of N₂O emissions to the application of nitrification inhibitors has also been investigated in the last few decades, particularly in the context of climate change mitigation. More recent studies have examined the effects of elevated CO₂ on N₂O in various agricultural contexts, including a variety of cropping systems. However, there are currently no available reports on the potential effects of the interaction between elevated CO₂ and the nitrification inhibitors on N₂O emissions from a winter wheat field under open-air conditions. We therefore measured N₂O flux using closed chambers at the Free-Air Carbon dioxide Enrichment (FACE) experimental facility in northern China. The target atmospheric CO₂ concentrations were 400 μL/L (ambient) and 550 μL/L(elevated) for treatments with and without the application of a nitrification inhibitor (Nitrapyrin). Nitrapyrin was applied twice (24% N-serve, 10 mg/kg soil) during the growing season-on day 1 and day 30 after fertilizer application. Measurements (0, 20, and 40 min after chamber closure) were taken from the start of the elongation stage until harvest (Triticum aestivum L. cv. Zhongmai 175). Measurements were taken daily for a week after each nitrapyrin application, and on a weekly basis from the application of nitrapyrin until harvest. The results showed that: 1) from the elongation stage to harvest, the elevated atmospheric CO₂ concentration increased N₂O emissions from the soil by 67.6% overall. Within a week of the first and second applications of the nitrification inhibitor, N₂O flux was increased by 58.1% and 78.7%, respectively, under conditions of elevated CO₂. 2) Nitrapyrin had no significant effect on N₂O emissions from the winter wheat field. The effect of the interaction between CO₂ concentration and nitrapyrin application on N₂O emissions was not significant. 3) N₂O flux was the highest after fertilization and irrigation, before declining gradually over the course of the season. In our study, elevated CO₂ stimulated N₂O emissions, possibly as a result of higher carbon (C) input into the soil and C substrate availability for denitrifiers. However, the increase in emissions was not mitigated by the application of nitrapyrin. The ineffectiveness of nitrapyrin observed in our study may be due to (i) the fact that the background ammonium (NH₄⁺) content in the soil was high at our study site, and/or (ii) the adsorption of the active ingredient of the inhibitor into the soil organic matter may be strong enough to reduce contact between the ingredient and NH₄⁺. Further research is required to substantiate these findings. Our results indicate that under future atmospheric CO₂ concentrations, it will be necessary to adopt appropriate agricultural management and cultivation practices in order to reduce N₂O emissions from winter wheat fields. This study provides implications for the use of nitrapyrin in the mitigation of N₂O emissions from winter wheat fields.