Abstract: Two amino acid ionic liquids (AAILs), viz., tetramethyl ammonium glycinate (N₁₁₁₁Gly) and tetramethyl ammonium lysine (N₁₁₁₁Lys) were supported on porous silica gel through impregnation evaporation method and used as the adsorbents for carbon dioxide. They were characterized by elemental analysis (EA), thermogravimetric analysis (TGA), nitrogen physisorption and Fourier transform infrared (FT-IR) spectroscopy; the effects of AAIL type, loading and temperature on their adsorption capacity towards carbon dioxide were investigated. The results illustrate that AAILs are successfully immobilized into the porous silica gel and the supported sorbents exhibit excellent performance towards carbon dioxide, i.e. fast adsorption rate and high capacity. At 303.15-323.15 K, the adsorption capacity reduces with the increase of temperature, whereas there is a optimal loading of ionic liquids to get highest adsorption capacity towards carbon dioxide. Under 30 ℃ and 0.1 MPa, the N₁₁₁₁Gly/SG adsorbent with a N₁₁₁₁Gly loading of 22.4% exhibits the highest CO₂ capture capacity, i.e. 41 mg/g, equivalent to 0.62 mol CO₂ per mol AAILs; moreover, 90% of the equilibrium adsorption amount can be achieved in 20 min. Furthermore, no obvious decrease in the adsorption capacity is observed after recycling for six times.