The adsorption behavior of CO2 molecules on B38 fullerene is investigated using density functional theory calculations. It is found that CO2 molecules act as a Lewis acid and are chemisorbed on the B-B bond surrounding the hexagon holes of B38. The stability of the CO2 adsorbed structures is assessed at different temperatures and pressures. Under P0=0.1 Mpa, the CO2 adsorption capacity of B38 is 17.04 and 2.43 mol/kg(B38) at T=200 and 300 K, respectively. The larger adsorption energy of CO2 compared to H2, N2, and CH4 molecules suggests that B38 fullerene might be used to separate CO2 from gas mixtures.