Purpose <p>Permafrost peatland ecosystems are sensitive to nitrogen changes because most of them are nutrient-limited, and the increase in atmospheric nitrogen deposition may influence greenhouse gas (GHG) emissions in these ecosystems. The purpose of this paper is to study the effects of increasing nitrogen availability on GHG emission rates and forms.</p> Methods <p>The nitrogen addition experiment was conducted at the Mohe Forest Ecosystem National Research Station. NH₄NO₃ was selected as the nitrogen source. GHG emissions and soil physical and chemical properties (such as temperature and moisture) were measured over a two-year nitrogen addition experiment (2021–2022) to assess their response to increased nitrogen availability (CK: no nitrogen addition; LN: 25&#xa0;kg N ha^–1 yr^–1; MN: 50&#xa0;kg N ha^–1 yr^–1; HN: 100&#xa0;kg N ha^–1 yr^–1) in a permafrost peatland.</p> Results <p>The results show that during the growing season of 2021–2022 (June – October), nitrogen addition resulted in cumulative increases of soil dark respiration CO₂ (12.92% – 40.63%), CH₄ (24.11% – 85.50%), and N₂O (26.19% – 269.05%) emissions during the growing season. Correlation analysis revealed a negative correlation between soil pH and soil dark respiration, CH₄ flux and N₂O flux (<i>P</i> &lt; 0.01).</p> Conclusions <p>Nitrogen addition mainly regulated GHG emissions through an increase in carbon and nitrogen substrates. GHG emissions increased significantly with rising nitrogen inputs with no saturation point detected. The stimulatory effect of high-nitrogen treatments on GHG emissions was most pronounced. Future GHG emissions projections from permafrost peatlands should account for both atmospheric nitrogen deposition and permafrost thaw-induced nutrient release to improve accuracy in climate models.</p>