Supported polyimide-titania hybrid membranes were prepared by sol-gel technique and characterized by the methods of ESEM,IR,TG-DTA,mercury porosimetry and gas permeability measuring apparatus to get their surface morphology,structure,thermal performance,pore size distribution and gas permeability properties．The results showed that new type structure of organic phase containing inorganic phase between polyimide and titania particle by bond conjunct was formed．The discomposing temperature was decreased with the increasing of TiO2 contents,and the thermal stability was better than polyimide materials under the temperature of 450℃．The pore size increased with the increasing of TiO2 contents,and pore size distribution tended to disperse．The permeability of N2,H2 and CO2 across the membrane were controlled by Knudsen diffusion,and the memebrane exhibited outstanding hydrophilicity since their permeation coefficients of H2O／N,are higher than the Knudsen diffusion values．