To improve the efficiency of electrolyte perturbed-chain statistical associatingfluidtheory–density functional theory (ePC-SAFT-DFT) calculation of the confined system, inthis work,first, the Chebyshev pseudo-spectral collocation method was extended to thespherical pores. Second, it was combined with the Anderson mixing algorithm toaccelerate the iterative process. The results show that the Anderson mixing algorithmcan reduce the computation time significantly. Finally, based on the accelerated ePC-SAFT-DFT program, a systematic study of the effects of the temperature, pressure, poresize, and pore shape on the CO2solubilities in the ionic liquids (ILs) confined inside the silicananopores was conducted. Based on the simulation results, to obtain high CO2solubilitiesin the ILs confined in silica, a better option is to use the silica material with a narrowspherical pore, and the IL-anion should be selected specifically considering that it has amore significant impact on the absorption enhancement effect.