The present invention relates to a synthesis method of high-purity amlodipine besylate. In particular, o-chlorobenzaldehyde, 4-(2-phthalyl imino radical ethoxy) acetoacetic ester and 3-amino methyl cro-tonate are used as raw materials for ring closure in an alcohol solvent, and when the amount of the 3-amino methyl cro-tonate is three times, the intermediate for ring closure can be prepared; the intermediate is refined by toluene/glacial acetic acid, dissolved in methylamine to form a salt in the aqueous solution, and the high-purity amlodipine besylate can be acquired after recrystallizationwith ethyl alcohol.