Large-pore mesoporous silica (MSU-J) with wormhole framework structure was prepared and modified with triethylenetetramine (TETA) by wet-impregnation. It was used as adsorbent for CO2. The hydrolyzing mesoporous silica was prepared by boiling the MSU-J in distilled water. CO2 adsorption capacity was investigated at different temperatures and TETA loadings. The results showed that adsorption capacity decreased with increase of adsorption temperature. Increase of TETA content increased CO2 adsorption. Repeated adsorption/desorption cycles showed that amine-impregnated materials were efficient in CO2 adsorption.