1. Extract naringin from grapefruit. Peel off the peel of grapefruit, dry it, crush it, and extract it with ethanol or other solvents to get naringin.
2. Hydrolyze naringin. The extracted naringin is added into weakly alkaline aqueous solution, and heated for a period of time to hydrolyze naringin into naringin and saccharides.
3. Separation and purification of naringin. The mixture obtained by hydrolysis reaction was filtered, concentrated and crystallized to obtain naringin with high purity.