NOVELTY - Preparing perfluorinated high-temperature proton conductor composite film comprises: (a) pre-treating Nafion film; (b) placing the pre-treated Nafion film into the drying oven to dry, placing the ionic liquid hydroxide-1-butyl-3-methyl imidazole into the container, completely soaking the dried Nafion film into the ionic liquid, placing into the drying oven to seal and react; (c) washing the Nafion-BMIM composite film by deionized water at room temperature, placing into the vacuum drying tank to dry; and (d) completely soaking the composite film into the phosphoric acid aqueous solution.    USE - The process is useful for preparing perfluorinated high-temperature proton conductor composite film (claimed).    ADVANTAGE - In utilizing the process, the prepared perfluorinated high-temperature proton conductor composite film has excellent conductivity at 80-160 degrees C and under condition without humidifying.    DETAILED DESCRIPTION - Preparing perfluorinated high-temperature proton conductor composite film comprises: (a) pre-treating Nafion film: soaking the Nafion film in hydrogen peroxide (H2O2) aqueous solution, deionized water of 70-90 degrees C, and sulfuric acid (H2SO4) aqueous solution for 0.5-2 hours in turn respectively, after washing by deionized water of room temperature, soaking the film into deionized water of room temperature for use; where the perfluorosulfonic acid film uses Nafion film; (b) placing the pre-treated Nafion film into the drying oven to dry, placing the ionic liquid hydroxide-1-butyl-3-methyl imidazole into the container, completely soaking the dried Nafion film with constant weight into the ionic liquid, sealing the container, placing into the drying oven to seal and react for 1-10 hours at 60-120 degrees C, taking out the container, naturally cooling at room temperature, taking out the film, wiping the ionic liquid on the surface, obtaining the Nafion/1-butyl-3-methylimidazolium (BMIM) composite film; (c) washing the Nafion-BMIM composite film prepared in (b) by deionized water at room temperature, and wiping the water on the surface of the composite film, placing at room temperature, after slowly vaporizing the water in the film, placing the composite film into the vacuum drying tank to dry into constant weight; and (d) completely soaking the Nafion-BMIM composite film treated in (c) into the phosphoric acid aqueous solution with concentration of 95-99.7% at room temperature; where the soaking time is 12-48 hours; and then taking out the composite film, wiping the surface of the composite film, obtaining the perfluorinated high-temperature proton conductor composite film doped with Nafion-BMIM/phosphoric acid (H3PO4).