Perovskite membrane precursor was prepared in this work using a sol-gel method. The perovskite precursor Sol was a rheopectic fluid and it exhibited Newtonian flow within 2 h of aging. After 24 h of aging, the flow became non-Newtonian. The thickness of the thin layer was approximately 2 mu m that was deposited on a macroporous alumina support pretreated with polyvinyl butyral. The precursor was dip-coated on the support to form a perovskite thin layer for use in the oxygen and nitrogen permeability experiment conducted at room conditions. From the permeability result, it appeared virtually impossible to separate oxygen from the oxygen/nitrogen mixture because of the value of the permeability that was nearly identical. From the separability experiment, however, the oxygen separation factor was found to be higher than the theoretical separation factor attributed to the Knudsen diffusion, suggesting the possibility of separation and enrichment of the gas from the binary mixture. The higher separability of oxygen was perceived to be attributable to the affinitive energy by the perovskite in the range between 11 - 19 kJ/mol.