NOVELTY - Preparation of organic-inorganic compound proton exchange film comprises adding dried copolymer into concentrated sulfuric acid, adding sulfonation product into ice water, filtering product and drying; dissolving sulfonated copolymer, and stirring; adding heteropoly acid additive into solution, stirring and dissolving; removing bubble and impurity of solution, adding half of solution into horizontal glass board, soaking polypropylene film in solution, shaping, and drying film; and adding remaining half of solution into surface of proton exchange film, shaping, drying film, and demolding.    USE - Method for preparation of organic-inorganic compound proton exchange film used for vanadium battery (claimed).    ADVANTAGE - The compound film is environment friendly, and has good vanadium resistant property, swelling property, proton conductivity, mechanical property and chemical stability. The single vanadium battery also has good property. The preparation of film is simple and easy for industrialized manufacturing, and has low cost.    DETAILED DESCRIPTION - Preparation of organic-inorganic compound proton exchange film comprises:    (A) adding dried copolymer into 95-98% concentrated sulfuric acid (10-40 pts.wt.) to conduct sulfonation reaction, adding sulfonation product into ice water, stirring, reducing pressure, filtering product and repeatedly washing to neutralize, and drying product to obtain sulfonated copolymer;    (B) dissolving sulfonated copolymer in high boiling point solvent to obtain 2-20% sulfonated copolymer solution, and stirring at 20-60 degrees C for 2-5 hours in water bath;    (C) adding 5-75% heteropoly acid additive into solution, stirring and dissolving at 20-60 degrees C for 2-10 hours in water bath;    (D) removing bubble and impurity of solution, adding half of solution into horizontal glass board having groove, soaking polypropylene film in solution at 10-70 degrees C for 4-18 hours, shaping via tape casting, pasting or soaking in glue, drying film to obtain proton exchange film with one compound surface; and    (E) adding remaining half of solution into surface of proton exchange film, shaping via tape casting, pasting or soaking in glue, drying film, and demolding in deionized water to obtain organic-inorganic proton exchange film.