Abstract: A zeolite composite membrane apparatus and method for preparing a novel continuous zeolite composite membrane. The method described results in formation of a thin polycrystalline continuous zeolite layer on the inner wall of a substrate container. The container may be a cylinder. After calcination, the zeolite composite membrane shows high permeability and high selectivity for single gas and for vapor/gas mixtures. The zeolite composite membrane formed has improved separation characteristics of shape selectivity and selective adsorption. The geometry of the membrane provides a high permeation area to volume ratio. The membrane is useful for high temperature gas separations and for membrane reactor applications.