The invention discloses a treatment method for improving the water resistance of an electrode foil for an aluminum electrolytic capacitor. The method comprises the steps of soaking an aluminum foil in water at 95 DEG C for 10 minutes; taking out the aluminum foil and putting the aluminum foil into 0.5% of an ammonium dihydrogen phosphate water solution for formation for 10 minutes; taking out the aluminum foil for washing; putting the aluminum foil into 0.3% of an ammonium dihydrogen phosphate water solution for formation for 10 minutes; taking out the aluminum foil for washing; putting the aluminum foil into 8% of a boric acid and 1% of an ammonium pentaborate water solution for formation for 10 minutes; putting the aluminum foil into a same tertiary water solution for formation for 30 minutes; putting the aluminum foil into a water solution with the same three-stage formation for formation for 10 minutes; carrying out treatment in 0.1%-3% of an organic phosphoric acid or organic phosphate solution at 50-80 DEG C for 5-10 minutes; taking out the aluminum foil for washing; putting the aluminum foil into a water solution with the same three-stage formation for formation for 10 minutes; putting the aluminum foil into 2% of an ammonium dihydrogen phosphate solution and steeping at 70 DEG C for 5 minutes; and taking out the aluminum foil and washing and drying the aluminum foil. The treatment method has the advantages that the electrode foil with high water resistance can be obtained, the voltage-rise time of a product after being boiled is shortened, the electrode foil is convenient to store and the storage life is prolonged.