A promising adsorbent for CO2 removal was prepared by introducing methyl-diethyl-amine (MDEA) into mesoporous silica SBA-15 using impregnation method. The MDEA modified adsorbents were characterized by X-ray powder diffraction (XRD) and nitrogen adsorption/desorption. Surface area, pore size and pore volume of MDEA-modified SBA-15 adsorbent decreased with the increasing of MDEA loading, while the loaded MDEA could not change the structure of the adsorbents. The adsorption performance of CO2 on the adsorbents was conducted in a dynamic setup. Dynamic adsorption performance changed with change of the amount of loaded MDEA. In addition, not only the adsorbent was regenerable by purging with the purified gas, but also the adsorption performance is stable in adsorption cycles. The results indicated that the MDEA modified adsorbents were novel for removing CO2 for biogas upgrading.