Disclosed is a method for the separation of S-(−)-amlodipine from a racemic amlodipine. Featuring the use of inexpensive L-tartaric acid as an optical resolution agent and DMAC as a solvent, the separation method allows the resolution of S-(−)-amlodipine from racemic amlodipine at high yield and to a satisfactory enantiomeric excess and thus is economically favorable and applicable to the mass production of the optical isomer.