Doped Polyaniline(PANI)/Polyimide(PI) membranes were prepared and the effects of PANI contents on the structural properties and gas permeation properties were studied. The polyamic acid(PAA) solution was prepared from 6FDA and ODA. The PANI/PI membranes were doped in 1M aqueous HCI solution for 24h. The structural characterizations of the membrane were examined by FT-IR, XRD and TGA. The gas permeation experiments with H2, CO2, O2, N2, and CH4 were carried out by variable pressure method at 30℃ and oatm. For all gases tested, the permeability coefficients of the doped blends decreased with increasing PANI content and the magnitude of permeabilities was in the order of H2 > CO2 > O2 > N2 > CH4. The permselectivities of the doped blends for H2/N2 and H2/CH4 increased with increasing PANI content.