A new membrane material containing facilitated transport groups for carbon dioxide has been synthesized through the hydrolysis of polyvinylpyrrolidone (PVP) obtained by radical polymerization. The composite membrane was prepared with the hydrolysate as the top layer and microporous membrane as the support. The permeation of pure CO2 and CH4 as well as a binary mixture Of CO2/CH4 through the composite membrane was measured. The effects of feed gas pressure, heat treatment and support membranes on the composite membrane performance were studied. The results show that the composite membranes possess better CO2 permeance and selectivity Of CO2 over CH4 than that of other fixed carrier membranes reported in literature.