Taking advantage of a property that heteropolyaicds (HPAs) are highly soluble in some polar organic solvents, HPA-imbedded polymer films(film catalyst) were prepared and their catalytic characteristics were studied. Furthermore, utilizing the permselectivity of the film catalyst for the organic chemicals, its application to the catalytic membrane reactor was discussed. It was revealed that an activity of the film catalyst was much superior to the corresponding bulk catalysts due to the fine and uniform dispersion of HPA throughout the polymer film, and that its acidic and redox function could be controlled, depending on the solvent used during the preparation of film catalysts. Possibility of an application of the catalytic polymer membrane reactor was established by the development of a coating technique of the film catalyst on a porous alumina tube. Preparation procedures, characteristics and application areas of HPA-polymer film catalysts and catalytic membranes were reviewed in this report. Typical examples of the application of these catalytic materials to the vapor-phase and liquid-phase catalytic reactions, the selective separation, and the catalytic membrane reactors were described.