A simple and precise method using high-performane. liquid chromatography was developed for the simultaneous determination of three bisbenzylisoquinoline alkaloids, namely tetrandrine, demethyltetrandrine and berbamine, in Stephania tetrandra S. Moore.A reversed-phase system consisting of chemically bonded ODS silica gel column and methanolacetonitrile-H2O (3: 1:1) containing 0.06% diethylamine as the mobile phase was used. The three alkaloids were completely separated within 10 min. The analytical results for various samples were presented.