Disclosed is a method for preparing benidipine hydrochloride, which comprising: 1) during the pre-treatment stage including acylchloridizing the main ring of dihydropyridine and then linking the side chain to synthesize directly benidipine hydrochloride, ultrasound technology is introduced, and the reactant material is dispersed and dissolved by untrasound to increase reaction rate; and/or 2) during the post-treatment stage, ultrasound technology is introduced and crude crystals or product obtained by heating to dryness of benidipine hydrochloride obtained via the method described above or any other synthetic routes is dissolved once more and then highly purified benidipine hydrochloride is obtained by untrasound.