Soil-emitted N₂O contributes to two-thirds of global N₂O emissions, and is sensitive to global change. We used DayCent model to simulate major plant–soil N cycling processes under different global change scenarios in a typical temperate mixed forest in north-eastern China. Simulated scenarios included warming (T), elevated atmospheric CO₂ concentration ([CO₂]) (C), increased N deposition (N) and precipitation (P), and their full factorial combinations. The responses of plant–soil nitrogen cycling processes including net N mineralization, plant N uptake, gross nitrification, denitrification and soil N₂O emission were examined. Concurrent increase of elevated [CO₂] and N deposition displayed most strong interactive effects on most fluxes. Using the results from experimental studies for evaluation, simulation uncertainty was highest under elevated [CO₂] and increased precipitation among the four global change factors. N deposition had a fundamental impact on soil N cycle and N₂O emission in our studied forest. Despite forest soil acting as a N sink for added N, scenarios which included increased N deposition showed higher cumulative soil N₂O emissions (summed up from 2001 to 2100). In particular, the scenario which included T, P, and N had the largest cumulative soil N₂O emission, which was a 24.4% increase over that under ambient conditions. Our study points to the importance of the interactive effects of global change factors on plant–soil N cycling and the necessity of multi-factor manipulation experiments.