The alpine meadow is the largest and most important ecosystem in northern Tibet. Recently, nitrogen deposition in Tibet has had a profound impact on carbon and nitrogen cycles in grassland ecosystems. To assess the impact of nitrogen deposition on greenhouse gas emissions from alpine meadows in northern Tibet, we conducted a nitrogen fertilizing experiment, using four fertilizing levels of 0, 7, 20, and 40 kg hm^-2 a^-1, in Nagqu County in the growing season in 2014. Our results showed that the impact on greenhouse gas emission varied with different levels of nitrogen deposition. Regarding daily variation, nitrogen significantly enhanced CO₂ emission but had no effect on the absorption of CH₄, or the emission of N₂O. Overall, nitrogen deposition significantly increased greenhouse gas emissions. The highest emission occurred with the N20 treatment, and there was a positive correlation among CO₂, net primary productivity (NPP), and total organic carbon (TOC) (P < 0.05). The total nitrogen (TN), NH₄⁺-N, and NO₃^--N were not correlated with CO₂ (P > 0.05), and the same pattern was observed in the relationship between CH₄ and TN/NPP/TOC/NH₄⁺-N/NO₃-N (P > 0.05). N₂O levels showed a significant linear correlation with NPP/TOC/NO₃-N (P < 0.05), but were not correlated with TN/NH₄⁺-N (P > 0.05). With additional nitrogen deposition expected in the future, greenhouse gas emissions would increase significantly and have a positive or negative feedback on climate change in Northern Tibet.