NOVELTY - A polysiloxane multiphosphonic acid-doped chitosan proton exchange film is manufactured by dissolving chitosan powder in aqueous acetic acid solution, stirring mixture, dissolving chitosan in mixture, and dissolving multiphosphonic acid and organosiloxane in deionized water. Organosiloxane solution is added to chitosan liquid and stirred. The multiphosphonic acid solution is added to mixed solution to obtain sol. The sol is placed in PTFE mold plate and dried. The PTFE mold plate is heat-processed, cooled and stripped.    USE - Polysiloxane multiphosphonic acid-doped chitosan proton exchange film.    ADVANTAGE - The polysiloxane multiphosphonic acid-doped chitosan proton exchange film can be prepared simply under mild reaction conditions and at high temperature, and has high proton conductivity even at high temperature, low humidity and anhydrous conditions.    DETAILED DESCRIPTION - A polysiloxane multiphosphonic acid-doped chitosan proton exchange film is manufactured by dissolving chitosan powder in aqueous acetic acid solution, stirring the mixture completely and uniformly, dissolving chitosan in the mixture to obtain chitosan liquid, and dissolving multiphosphonic acid and organosiloxane solution in deionized water to obtain 0.033-0.1 mol/l multiphosphonic acid solution and 0.2-0.4 mol/l organosiloxane solution. The organosiloxane solution is added to the chitosan liquid at room temperature and stirred uniformly to obtain mixed solution, where the volume ratio of the organosiloxane solution and chitosan liquid is 1:1-1:2. The mixed solution is put in ice water mixed bath and multiphosphonic acid solution is added slowly dropwise to the mixed solution, where the molar ratio of silicon element and phosphorus in the multiphosphonic acid solution is 1/4-1/1. The mixed solution is stirred for 12-24 hours to obtain sol. The sol is placed in PTFE mold plate and dried under vacuum at 40-60 degrees C for 4-8 hours. The PTFE mold plate is heat-processed at 100 degrees C, 120 degrees C and 150 degrees C for 2 hours and cooled. The PTFE mold plate is stripped to obtain the finished product. An INDEPENDENT CLAIM is also included for a method for preparing the polysiloxane multiphosphonic acid-doped chitosan proton exchange film, which involves performing the above-mentioned steps.