The invention relates to a preparation method of a flaky nickel-doped nickel hydroxide electrode material. The preparation method is characterized in that calcium hydroxide slurry with the concentration being 10 to 20g/L and a nickel ion solution with the concentration being 0.2 to 0.5mol/L are mixed and stirred; firstly, the mixture partially takes an ion exchange reaction; a mixed system after stirring is filtered, washed and dried, and is reduced in hydrogen atmosphere to obtain a nickel/calcium oxide compound; then, 1 to 10g of the nickel/calcium oxide compound and 50ml of the nickel ion solution are mixed to take an ion exchange reaction; a mixed system after stirring is filtered, washed and dried to obtain the nickel-doped nickel hydroxide electrode material. When the nickel-doped nickel hydroxide electrode material obtained by the method is used as an electrode material to be applied to supercapacitor energy storage, the excellent capacitive performance is realized.