In view of the growing environmental requirement of recent years to reduce the amount of CO2 gas in the atmosphere. we have developed a microporous SiO2-ZrO2 membrane for CO2 separation from exhaust gases at high temperature. The SiO2-ZrO2 membrane was prepared by a sol-gel method, in which zirconium oxychloride and tetra-n-propylammonium bromide were used as the ZrO2 source and as a template, respectively. The membrane thus obtained exhibited a high selectivity of CO2/N-2 of 7 at 573 K, which was attributed to its pore size of close to 0.6 nm.