Polyaniline(PANI)/Polyimide(PI) blended membranes were prepared and the effect of mixing ratio of PANI and PI on the structural properties and the gas transport properties was studied. The polyamic acid(PAA) solution was prepared from 6FDA and ODA in NMP solvent. The PANI/PI blended membranes were obtained by mixing PAA solution and PANI solution. The gas permeation experiments with H₂, He, O₂, N₂, CO₂, and CH₄ were carried out by variable pressure method at 30 ℃ and 5atm. For all gases tested, the permeability coefficient of PANI/PI blended membranes was higher relative to that of polyaniline and the separation factors for the blended were comparable to polyaniline.