A static chamber and gas chromatography were employed to investigate the effects of low- and high-intensity burning on CH₄, CO₂ and N₂O discharge by larch swamp of the Lesser Xing'an Mountains. The results show that the average seasonal CH₄, CO₂ and N₂O fluxes were respectively 409.7, 508.1, and 597.8 mg · m^–2 · h^–1 at sites where there was no burning, 0.057, 0.134 and 0.043 mg · m^–2 · h^–1 at sites with low-intensity burning, and -0.0063, 0.0021 and 0.0059 mg · m^–2 · h^–1 at sites with high-intensity burning. Fire disturbance increased CO₂ fluxes by 24.0%-45.9% and increased CH₄ fluxes by 135.1% in the case of light burning and decreased CH₄ fluxes by 31.3% in the case of heavy burning, and shifted the burning site from a N₂O sink to a N₂O source. Severe fire disturbance greatly affected the seasonal dynamics of CO₂ fluxes, and the fire intensity affected seasonal variations in CH₄ and N₂O fluxes. CO₂ emissions at the study sites had significant negative correlation with the water level, and the temperature had significant positive correlation with the soil temperature. CH₄ emissions from the site at which there was low-intensity burning had significant negative correlation with the level of the water table and significant positive correlation with the soil temperature at 0 cm. The flux of CH₄ emissions from the site with low-intensity burning had positive correlation with air temperature and some individual soil temperatures, whereas that from the site with high-intensity burning and the flux of N₂O emissions from sites with low-intensity, high-intensity and no burning had no relationship with soil temperature or the level of the water table. The CO₂ emission intensity at burning sites and CH₄ emitted from the lightly burning site were both higher than respective values for the site where there was no burning, but the CH₄ emission intensity from the heavily burning site was less than that at the site where there was no burning. Fire disturbance converted a site from a weak sink of N₂O into a weak source. The global warming potential of the fire-disturbance sites increased by 1/4-1/2 relative to that of the site with no burning, with the potential increasing with the increasing intensity of the fire disturbance. Therefore, wetland management should be strengthened in view of the effective control of greenhouse gas emissions in wetlands, especially in terms of avoiding intense fire. In addition, both before and after fire in the investigated forest swamp, the effect of greenhouse gases mainly depends on the potential of soil CO₂ emissions (99%), and the role of N₂O CH₄ emissions is very small (a contribution of less than 1%). It is thus necessary to research the carbon cycle.