The invention discloses a preparation method of a nickel-hydrogen battery positive electrode material. The preparation method comprises the steps of preparing foamed nickel used as an electrode substrate material; growing three-dimensional graphene on a surface of the electrode substrate material; forming nickel hydroxide on a surface of the three-dimensional graphene; and obtaining the nickel-hydrogen battery positive electrode material which is combined from the three-dimension graphene, the nickel hydroxide and the electrode substrate material. According to the preparation method of the nickel-hydrogen battery positive electrode material, the nickel-hydrogen battery taking the provided composite material of the foamed nickel, the three-dimensional graphene and the nickel hydroxide as the positive electrode material has high capacity and excellent cycle stability, and the service lifetime of the nickel-hydrogen battery is at least 2-4 times of the service lifetime of an existing nickel-hydrogen battery in the market.