Activated carbon flue gas purification technology can simultaneously remove various pollutants in flue gas with high removal efficiency, and has been widely applied to flue gas treatment in industries including iron and steel, non-ferrous metallurgy and coal-fired power generation. However, heat accumulation easily forms hot spots on activated carbon after adsorbing flue gas pollutants, bringing potential spontaneous combustion hazards. Therefore, systematic evaluation of the thermal stability of activated carbon under various adsorption conditions is of great engineering guiding significance. In this work, thermogravimetry-differential thermal analyzer (TG-DTA) was adopted to conduct thermal oxidation combustion experiments of activated carbon. The thermal stability characteristics of activated carbon under the coupling effects of single CO2, SO2, NOx atmospheres, multi-component mixed flue gas and different adsorption saturations were systematically investigated. Key kinetic parameters such as ignition temperature, burnout temperature, heat release characteristics and apparent combustion activation energy were quantitatively analyzed synchronously, and the coupling regulation mechanism between multi-pollutants and adsorption saturation was clarified. The results showed that CO2, SO2 and mixed atmospheres could raise the ignition temperature of activated carbon by 18~77℃, and reduce the average maximum heat release by 8% and 9% compared with raw activated carbon under CO2 and SO2 atmospheres, which remarkably suppressed spontaneous combustion risks. On the contrary, NOx atmosphere exerted an opposite effect, and the highest spontaneous combustion risk occurred at 100% adsorption saturation: the ignition temperature dropped to 340℃, the temperature corresponding to the maximum heat release rate decreased by 26℃ relative to raw carbon, and the average maximum heat release increased by 0.5 mW/mg. The kinetic barrier of carbon oxidation was greatly reduced, and the spontaneous combustion tendency was significantly intensified. The complex kinetic characteristics were governed by the mutual restriction of multiple effects, including competitive adsorption of CO2 on active sites, catalytic combustion promotion induced by chemically adsorbed NOx, and surface passivation and combustion inhibition from SO2 adsorption. This study identifies the distinctive spontaneous combustion risk of activated carbon with high adsorption saturation under NOx atmosphere, reveals the synergistic regulation law of coexisting multi-pollutants on the thermal oxidation properties of activated carbon, and provides theoretical support for the safe and stable operation of industrial activated carbon flue gas purification equipment.