The invention relates to an activate method of membrane electrode of fuel battery, wherein the fuel battery comprises baffle plates, an anode room 4, a cathode room 5, and a membrane electrode. The membrane electrode is between the baffles, the membrane electrode comprises an anode 1, a cathode 2, and an atom exchange membrane 3 between the anode 1 and the cathode 2, the anode room 4 is between the anode 1 and the baffle plates, and the cathode room 5 is between the cathode 2 and the baffle plates. The method comprises that connecting the anode and cathode of a power supply respectively with the anode 2 and the cathode 2 of fuel battery, adding one external power on the fuel battery, filling fuel into the anode room 4 before closing the power supply, and filling water into the cathode room 5. The active area of membrane electrode activated by the invention is significantly improved, and therefore, the power of fuel battery is improved. The inventive activate method ha simple operation, short activate time, and better repeatability.