NOVELTY - Preparing hindered alcohol modified palladium-Nafion (RTM: Sulfonated tetrafluoroethylene based fluoropolymer-copolymer) composite membrane comprises impregnating the preprocessed Nafion (RTM: Sulfonated tetrafluoroethylene based fluoropolymer-copolymer) membrane in palladium ion solution, applying different voltage signals for direct current electric field or applying square wave and a sinusoidal signal for pulsed electric field, maintaining impregnating time, reducing palladium ion into palladium atom, and placing in sulfuric acid solution to convert into hydrogen ion form.    USE - The method is useful for preparing hindered alcohol modified palladium-Nafion (RTM: Sulfonated tetrafluoroethylene based fluoropolymer-copolymer) composite membrane.    ADVANTAGE - The method is easy to operate and control, and adopts impregnation reduction processing method to reduce methanol permeability of membrane, thus improves the proton conductivity and the performance of the direct methanol fuel cell (DMFC).    DETAILED DESCRIPTION - Preparing hindered alcohol modified palladium-Nafion (RTM: Sulfonated tetrafluoroethylene based fluoropolymer-copolymer) composite membrane comprises impregnating the preprocessed Nafion (RTM: Sulfonated tetrafluoroethylene based fluoropolymer-copolymer) membrane in palladium ion solution (0.002-0.1 mol/l) at 20-80 degrees C, simultaneously applying different voltage signals on the both the sides of Nafion membrane (RTM: Sulfonated tetrafluoroethylene based fluoropolymer-copolymer) membrane for direct current electric field, where the amplitude of the applied voltage is 0.5-5 V or applying square wave and a sinusoidal signal for pulsed electric field, where the voltage amplitude value is 0.1-5 V, the duty ratio is 5-50%, and the frequency is 102-108 Hz, maintaining the impregnating time for 30-120 minutes, taking out the impregnated membrane, impregnating in an aqueous solution containing reducing agent, reducing palladium ion into palladium atom, where the reduction temperature is maintained at 40-80 degrees C, and placing the palladium-Nafion (RTM: Sulfonated tetrafluoroethylene based fluoropolymer-copolymer) composite membrane in sulfuric acid solution to convert into hydrogen ion form.