Abstract: This invention relates to the petrochemical industry, in particular, to a method for improving the storage stability of biodiesel fuel via using an antioxidant additive. A method for improving the storage stability of biodiesel fuel, comprising addition of an alkylphenol-based antioxidant additive via providing an initial solution that contains 6 to 48 mass % of the alkylphenol-based composition comprised of, mass %: 2,6-di-tert-butyl-4-methylcyclohexanone—0.2-0.3; 2,6-di-tert-butylphenol—0.7-6.0; 2-sec-butyl-6-tert-butyl-p-cresol—1.5-5.0; 4,6-di-tert-butyl-o-cresol—3.0-8.0; 2,4-di-tert-butylphenol—0.3-0.5; 2,4-di-tort-butyl-6-dimethylaminomethylphenol—2.0-5.0; 4,4-methylene-bis(2,6-di-tert-butylphenol)—0.1-0.3; and 2,6-di-tert-butyl-4-methylphenol—to the balance, dissolved in biodiesel fuel; and adding the solution of the composition to the biodiesel fuel to reach a concentration of the composition of from 0.002 to 1.6 mass % based on the entire biodiesel fuel solution.