Abstract: In order to solve the problem that the single effect of micro-pore size distribution and nitrogen content of nitrogen-doped carbon materials on CO₂ adsorption are difficult to quantify, a slit pore model of carbon-based adsorbents was constructed, and the effects of pore sizes, nitrogen doping amounts and adsorption temperature on CO₂ adsorption and flue gas separation performance were quantitatively studied by Monte Carlo simulation.The adsorption mechanism was analyzed from the perspective of relative concentration distribution of adsorbents.The results show that CO₂ adsorption capacity is affected by the synergistic effect of pore size distribution and nitrogen doping, and the narrow micro-pores below 0.8 nm have a greater effect on the adsorption capacity.The maximum CO₂ adsorption capacity at 0.8 nm in the simulated pore sizes range is 6.082 mol·kg^-1 at 1.5×10⁵ Pa, and nitrogen doping can improve the separation coefficient of flue gas.The research results can provide a reference for the preparation, modification and practical application of carbon-based adsorbents.