This study examines the impact of CO₂ storage on the pore and molecular structures of coal in unminable coal seams. Low-temperature liquid nitrogen adsorption, low-temperature CO₂ adsorption, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Raman spectroscopy (Raman) experiments were employed. The evolution rules of pore structure, surface functional groups, macromolecular structure, and microcrystalline structure of coal after CO₂ adsorption at different pressures were investigated. The results showed that, after CO₂ adsorption, the cumulative specific surfacearea and cumulative pore volume of micropores decreased. In contrast, the cumulative specific surface area and cumulative pore volume of mesopores and macropores increased. The average pore size of micropores increases overall, and the micropores in the pore structure transition to a direction that favors mesopores and macropores. At the same time, the total content of aromatic hydrocarbons incoal decreased, the aromatic layer spacing d₀₀₂ increased, the microcrystalline stacking height L_c, the average number of crystal stacking layers n, the aromaticity f_a decreased, the content of oxygen-containing functional groups and hydroxyl groups increased, the content of —CH₂— decreased, the content of —CH₃ increased slightly, and the CH₃/CH₂ value increased. It shows that after the adsorption of CO₂ by coal, the large aromatic structure developed to the small aromatic structure, the branched chain on the aromatic ring gradually became shorter and increased, the aromatic microcrystalline structure was destroyed, and the aromatic layer was more loosely accumulated, resulting in a decrease in the degree of crystallization. With the increase of CO₂ adsorption pressure of coal, the peak position difference d_(G-D) between D peak and G peak decreases, the intensity ratio I_D/I_G, half peak width of D peak (FWHM-D), half peak width of G peak (FWHM-G) and W_D/W_G values increased, and the peak area ratio A_S/A_total, A_S/A_D, A_D/A_G, A_(GR+VL+VR)/A_D values representing the defect structure also increased, it indicates that after coal adsorbed CO₂ under different pressure, the macromolecular structure in coal expanded and cracked, the proportion of graphite structure decreased and the proportion of impurity structure increased. The coal structure as a whole develops in the direction of increasing disorder. The research results provide a theoretical basis for the influence of geological storage of CO₂ on the microscopic properties of coal. The research results provide a theoretical foundation for understanding the impact of geological CO₂ storage.