NOVELTY - Preparing high temperature polyimide proton exchange film comprises preparing nitrogen-containing heterocyclic polyimide material by adding dianhydride monomer, sulfonated diamine monomer, nitrogen-containing diamine monomer, benzoic acid and triethylamine into a reactor under nitrogen atmosphere, adding aprotic polar solvent, polymerizing, adding acetone, filtering, washing to obtain nitrogen-containing polyimide material, dissolving in aprotic polar solvent, degassing, curing, removing protonated triethylamine, vacuum drying to obtain film, soaking film in phosphoric acid system and drying.    USE - The method is useful for preparing high temperature polyimide proton exchange film (claimed).    ADVANTAGE - The method provides product, which can be used at more than 100 degrees C, solves the problem of hydrolytic stability of the product, thus improving battery efficiency and has good mechanical properties.    DETAILED DESCRIPTION - Preparing high temperature polyimide proton exchange film comprises (a) preparing nitrogen-containing heterocyclic polyimide material under nitrogen atmosphere, adding dianhydride monomer, sulfonated diamine monomer, nitrogen-containing diamine monomer, benzoic acid and triethylamine into a reactor, the mol ratio of dianhydride monomer, sulfonated diamine monomer, nitrogen-containing diamine monomer is 1:x:(1-x), where x is 0-1, the molar amount of benzoic acid as acid dianhydride monomer is 1-3 times, the molar amount of the sulfonated diamine monomer is 2-4 times, adding aprotic polar solvent for high temperature polymerization at 150-200 degrees C for 6-16 hours, cooling, adding acetone, filtering, washing to obtain nitrogen-containing polyimide material, (b) dissolving the resulting material in aprotic polar solvent, degassing the solution, curing to form film, removing protonated triethylamine, washing with water, vacuum drying to obtain nitrogen-containing heterocyclic ring polyimide film, soaking the film in phosphoric acid system, drying to obtain phosphoric acid doped polyimide film, which is high temperature polyimide proton exchange film, or dissolving the polyimide material in aprotic polar solvent to obtain mixed solution, where the mixed solution has a solid content of 5-10%, adding phosphoric acid into the mixed solution, heating and stirring, ultrasonically processing, curing to obtain phosphoric acid doped polyimide film, which is high temperature polyimide proton exchange film.