The invention provides a preparation method for a composite material for energy storage elements, which includes the following steps: (1) graphene oxide, meso-erythritol, coniferyl alcohol, tea cake meal, lignin, xylan, lactose and distilled water are mixed and stirred; (2) mixture is loaded into a hydrothermal reaction kettle and heated, and temperature is kept; (3) the mixture is cooled to room temperature, filtered, washed to be neutral and dried, so that a product A is obtained; (4) the product A, potassium hydroxide, sodium hydroxide and distilled water are mixed and stirred; (5) sucrose fatty acid ester, quillaic acid, quercetin, paraben, propylgallate, n-butyl stearate and isopropanol are mixed and stirred; (6) the mixtures are mixed, put into a tube furnace and sintered; (7) the sinter is cooled to room temperature, washed to be neutral and dried, so that the composite material is obtained. The specific capacitance value of the material prepared by the method disclosed by the invention is extremely high, the energy density is much higher than the energy density of conventional energy storage elements, the efficiency of discharge is high, moreover, the composite material can show good cycle stability, and the repetition utilization rate is high.