NOVELTY - Preparation of a fire-resisting boron orthophosphate-poly(2,5-benzimidazole) (BPO4-ABPBI) nanometer compound proton exchange film for fuel battery, comprises: (a) adding boron orthophosphate and dispersant in leucinocaine solution of poly(2,5-benzimidazole); (b) pouring the nanometer dispersing system to a clean glass board; (c) soaking the glass board and the wet film to deionized water; (d) soaking it in 10% of sodium hydroxide solution and 10% of diluted aqueous ammonia; (e) washing the alkaline film with deionized water; and (f) soaking the neutral film in 50-70% of phosphoric acid.    USE - The process is useful for preparing a fire-resisting boron orthophosphate-poly(2,5-benzimidazole) (BPO4-ABPBI) nanometer compound proton exchange film for fuel battery (claimed).    ADVANTAGE - In utilizing the process, the prepared fire-resisting boron orthophosphate-poly(2,5-benzimidazole) nanometer compound proton exchange film for fuel battery has excellent comprehensive performances, and uses materials produced from industrial scales.    DETAILED DESCRIPTION - Preparation of a fire-resisting boron orthophosphate-poly(2,5-benzimidazole) (BPO4-ABPBI) nanometer compound proton exchange film for fuel battery, comprises: (a) adding boron orthophosphate (BPO)4 and dispersant in leucinocaine solution of poly(2,5-benzimidazole) and controlling mass of the BPO4 to be 5-30% of total mass of poly(2,5-benzimidazole) and BPO4; where the dispersant takes 0.5-1% of mass of the BPO4; using polyethylene glycol (PEG), sodium dodecyl benzene sulfonate (SDBS), or n-butyl ammonium bromide (TBAB) as the dispersant; grinding for 2 hours to obtain nanometer system; standing for 30 minutes at 80-85?C to make the bubbles in the nanometer dispersing system disappear; (b) pouring the nanometer dispersing system obtained in (a) to a clean glass board while it is hot, and quickly using wet film preparing device to obtain wet film; (c) soaking the glass board and the wet film to deionized water together, and obtaining acidic film when the yellow semitransparent film automatically falls off; (d) fishing out the acidic film, soaking it in 10% of sodium hydroxide (NaOH) solution and 10% of diluted aqueous ammonia for 24 hours, and removing acidic substance like leucinocaine contained in the acidic film to obtain alkaline film; (e) washing the alkaline film with deionized water until the pH value is 6.00-8.00 to obtain neutral film; and (f) soaking the neutral film in 50-70% of phosphoric acid (H3PO4) solution to soak for 2-7 days, taking it out, and absorbing the H3PO4 solution adhered on surface of the film with absorbent paper to obtain finished product proton exchange film, and controlling thickness of the finished product film to be 40-120 mu m.