Amino acids were used to modify macroreticular ion exchange resin for the adsorptive capture of CO2. Adsorption isotherms, adsorption rate curves, heats of adsorption, and gas separation performance were determined. It is found that the adsorption capacity of the resin increases significantly after the loading of amino acids. The adsorption progresses rapidly and reaches equilibrium within 3 min. The adsorption capacity decreases with the increasing temperature, and room temperature is a suitable condition that enables high adsorption of CO2. The adsorbent can be promoted by water vapor in removing CO2 effectively from gas mixtures. Ten continuous adsorption-desorption cycles was performed, showing that the adsorbent is of good regeneration performance and the adsorption capacity keeps at about 0.9 mmol/g after regeneration.