【Objective】Nitrogen deposition serves as the primary source of external nitrogen input in forest ecosystems, while litter decomposition is the key process of carbon and nitrogen cycling. Both nitrogen deposition and litter decomposition can modulate forest soil nitrous oxide (N2O) emission and methane (CH4) uptake. Moso bamboo (Phyllostachys edulis) forest is a unique forest type in China’s subtropics, with great carbon sequestration potential. However, the effects of nitrogen deposition, litter decomposition, as well as their interactions on Moso bamboo soil N2O emissions and CH4 uptake remain poorly understood. Thus, this study aimed to investigate how different nitrogen forms, litter types, and their interactions affect soil N2O and CH4 fluxes.【Methods】A 180-day constant-temperature microcosm experiment was conducted using the soil from a Moso bamboo forest. Two nitrogen forms (inorganic nitrogen: ammonium nitrate; organic nitrogen: urea + glycine), three litter types (Parathelypteris glanduligera, Moso bamboo, and Ardisia japonica), their pairwise combinations, and a control (no nitrogen or litter addition), totaling 12 treatments, were included in this study to investigate how different nitrogen forms, litter types, and their interactions affect soil N2O and CH4 fluxes.【Result】The results show that both nitrogen and litter additions significantly increased N2O emissions, but an antagonistic interaction appeared when they were applied concurrently and its magnitude was primarily driven by nitrogen form. Nitrogen and litter additions indirectly promoted N2O emissions by mainly altering soil pH, DOC and WSN, and then MBC and MBN. For CH4, both nitrogen and litter additions significantly enhanced CH4 uptake. Their combined application also generated an antagonistic interaction. However, this effect was independent of nitrogen form and litter type. Overall, nitrogen and litter additions promoted CH4 uptake primarily through changing soil pH and increasing DOC and NH4+-N concentrations.【Conclusion】This study revealed that the form of nitrogen deposition and litter type interactively regulate soil N2O emission and CH4 uptake in Moso bamboo forests. These findings provide theoretical support for litter management and greenhouse gas mitigation strategies in Moso bamboo forests under high nitrogen deposition.