The invention relates to a preparation method of high-purity prunetin, belonging to the field of natural pharmaceutical
chemistry. The preparation method of the high-purity prunetin comprises the following steps of: (1)
grinding Qamdo
caragana as a
raw material, ultrasonically extracting by using 5-8 times of low-carbon
alcohol, concentrating an extracting solution at a reduced pressure, adding a right amount of water to the concentrated solution for dispersion, adding
polyamide resin for adsorption, carrying out
gradient elution by using the water and the
alcohol, collecting target components, concentrating at a reduced pressure, then extracting by using
ethyl acetate, and concentrating the extracting solution at a reduced pressure to obtain the concentrated solution; (2) sufficiently mixing
chloroform,
methanol and an acidic
aqueous solution in a separating funnel, standing for layering, then taking top phases as immobile phases, filling into
reflux chromatography columns, starting a principal
machine, pumping bottom phases as mobile phases, injecting the concentrated solution through a
sampling valve after balancing, collecting components according to a
detector map, recovering regents, and
drying to obtain the high-purity prunetin. The invention has the advantages of easiness in operation of a process, short production period, high yield and suitability for industrialized preparation.