The invention relates to a preparation method of high-purity chlorogenic acid. The method comprises the following steps: S1, taking a honeysuckle medicinal material, crushing, adding into 15-25 timesby weight of pure water, and soaking for 2-4 hours; S2, adding hydrochloric acid to adjust the pH value to 3-4, heating to 45-60 DEG C, extracting twice, and filtering to obtain a first-stage extracting solution; S3, directly loading the first-stage extracting solution obtained in the step S2 on a polyamide column, performing gradient elution by adopting an eluent containing 10-40 vol% of an extracting agent, and collecting the fractions to obtain a second-stage extracting solution; S4, concentrating the second-stage extracting solution obtained in the step S3 to 8-20% of the original volume of the first-stage extracting solution so as to obtain a third-stage extracting solution, adding ethyl acetate according to a volume ratio of the third-stage extracting solution to the ethyl acetate of1:(3.5-4.5), extracting twice, and combining filtrates to obtain a fourth-stage extracting solution; and S5, concentrating the fourth-stage extracting solution obtained in the step S4 under reduced pressure until the volume of the fourth-stage extracting solution is 75-88% of the original volume of the fourth-stage extracting solution, and refrigerating and crystallizing to obtain the chlorogenicacid. The method has the advantages that impurities are removed to a large extent, and the purity of chlorogenic acid is effectively improved.