In recent years, the fixed carrier membranes for CO2, especially the membranes having amine moiety[1-3] have been investigated extensively. Matsuyama et al[4] found the performance of water-containing membranes was better than that of dry membranes. The selectiviy of the containing water membrane was 3-4 times the values of the dry membrane, while the permeance of the containing water membrane was higher about one order of magnitude than that of dry membrane. They thought the mechanism of carrier transport may be different for these two cases. The facilitated transport of CO2 is expected to be attributable to the weak acid-base interaction between CO2 and amine groups in dry conditions. In the case of the wet membrane, CO2 is transformed into the small and mobile ion HCO-3 because of interaction between CO2, water and amine groups. Thus water is very important in facilitated transport of CO2 through membrane,but no one reports water can facilitate transport of CO2 as a carrier.