The invention relates to a preparation method of an organic / inorganic compound proton exchange membrane used for a fuel battery. The method comprises the following steps: firstly, N, N-dimethyl acetamide solution with 10 to 20 percent of polysulfone amide is prepared, phosphotungstic acid powder is added into the solution, silica sol is added after the solution is uniformly mixed, ultrasound treatment is performed, and the ratio of the general weight of the phosphotungstic acid and SiO2 and the weight of the polysulfone amide is 20:80 to 50:50; secondly, the glue spreading speed of a spin coater is adjusted, the mixed liquor polysulfone amide, the phosphotungstic acid and the SiO2 which are uniformly mixed is dropped on a glass plate, membrane production is performed, and after the membrane is dried, the membrane is put in a water bath to be stripped. The process of the method is simple, the production cost is low, and large scale production can be performed, all the water ratio, the mechanical strength and the thermal stability of the prepared exchange membrane reach or exceed the perfluorosulfonic acid Nafion membrane.