NOVELTY - Method for producing brassinosteroid and brassinosteroid-like plant bioactive substance, involves extracting wash liquid containing the bioactive substance using ester type extraction solvent, where the liquid is generated during purification of fatty acid ester from crude glycerol, adding glycerol and glycol-type solvent having boiling point higher than the extraction solvent to the extract, and heating and carrying out pressure reduction of the extract to obtain concentrated plant bioactive substance.    USE - The method is useful for producing brassinosteroid and brassinosteroid-like plant bioactive substance used in composition (claimed) for stimulating stress tolerance, growth and vascular differentiation of plant e.g. cucumber, Japanese radish, sunflower, confederate rose and carnation, improving bioactivity of plant, and diseases and pest resistance of plants, and repelling insects.    ADVANTAGE - The method is cost-effective as it utilizes industrial waste, requires less labor, and enables high yield of the bioactive substance with high purity. The substance exhibits high bioactivity even in ultra low amount. The method prevents emission of carbon dioxide and thus global warming can be prevented.    DETAILED DESCRIPTION - Method for producing brassinosteroid and brassinosteroid-like plant bioactive substance, involves (a) obtaining wash liquid containing the bioactive substance, where the liquid is generated during purification of fatty acid ester from crude glycerol produced as byproduct during manufacture of fatty acid ester of vegetable oil, extracting the obtained wash liquid using ester type extraction solvent chosen from ethyl acetate, butyl acetate, ethyl propionate and butyl propionate, adding glycerol and glycol-type solvent having boiling point higher than the extraction solvent to the extract, and heating and carrying out pressure reduction of the extract to obtain concentrated plant bioactive substance; (b) extracting the bioactive substance from waste edible oil using solvent having dielectric constant of 20-40; (c) extracting the bioactive substance from the wash liquid using solvent having dielectric constant of 3-20; or (d) extracting the bioactive substance from waste edible oil and the wash liquid using solvent having dielectric constant of 3-40. An INDEPENDENT CLAIM is included for brassinosteroid and brassinosteroid-like plant bioactive substance, which are produced by the above method.