Preparation method of myricetin

The invention provides a preparation method of myricetin. The preparation method comprises the following steps: mixing dihydromyricetin with alcohols, then adding a sodium hypochlorite solution and a catalyst to carry out reactions, and after the reactions, keeping on adding a sodium hypochlorite solution to obtain myricetin; wherein the alcohol is methanol or ethanol, and the catalyst is anhydrous aluminum trichloride or anhydrous iron trichloride. According to the preparation method, dihydromyricetin is taken as the primary raw material, myricetin is prepared from dihydromyricetin through semi-synthesis, dihydromyricetin is extracted from vine tea, the content is 98% or more, the cost is low, the operation is simple, the product yield is high, the product does not need refinement, the content is 98% or more, and the preparation method is suitable for industrial production.