A negative-electrode plate, a preparation method thereof, and a secondary battery, a battery module, a battery pack, and an electric apparatus including such negative-electrode plate are provided. The negative-electrode plate includes an alkali metal layer and a polymer film layer provided on at least one surface of the alkali metal layer. Surface resistivity of the polymer film layer gradually increases in a thickness direction of the polymer film layer away from the alkali metal layer. When the negative-electrode plate is used in a secondary battery, lithium dendrites can be effectively inhibited.