The invention discloses a method for preparing high-purity phloridzin by virtue of apple tree branches. The method comprises the steps of raw material pretreatment, supercritical CO2-enzyme extraction, centrifugal partition chromatography purification and the like, and thus, the high-purity phloridzin is finally obtained. The method is applicable to preparation of the high-purity phloridzin with the apple tree branches as raw materials. According to the method, a supercritical CO2 extraction technology is combined with an enzyme-assisted extraction technology, and an enzymolysis process is implemented in supercritical CO2, so that enzymolysis effects and promotion effects on phloridzin extraction are greatly improved; in addition, supercritical CO2 extraction is high in selectivity, an entrainer is not required, and the product is easy to separate and high in purity; the extraction rate of the phloridzin is effectively increased, the high-purity phloridzin is obtained, the separation and purification time is saved, the yield is high, preparation procedures are simplified, and the method is a safe and efficient apple phloridzin extraction process, and has broad application prospect.