Abstract: Bentonite was modified by an organic amine (polyethylenimine) through a physical impregnation method. Physical and chemical properties of samples were characterized by X-ray diffraction (XRD), N₂ adsorptiondesorption measurement, and elemental analysis. CO₂ adsorption performances of samples were finally investigated. It was demonstrated that CO₂ adsorption capacity of bentonite was significantly improved after amine modification from 6 mg/g to 47 mg/g. Furthermore, the aminemodified bentonite was very stable in the cyclic CO₂ adsorptiondesorption experiments.