Preparation of high-purity ellagic acid

The invention discloses a preparation method of high-purity ellagic acid; tara powder is taken as raw material, extracted by purified water or 50-percent to 90-percent ethanol or a methanol water solution, hydrolyzed by concentrated sulfuric acid or hydrogen peroxide, purified by using diethylamine or triethylamine and crystallized, thus obtaining the high-purity ellagic acid; the method has simple technique and is suitable for industrialized production.