Abstract: A simple and precise method using ion-pair high permance liquid chromatogra-phy was developed for the simultaneous determination of four isoquinoline alkaloids ,namelyprotopine,corynoline,acetylcorynoline and tetrahydrocoptisine in Corydalis bungeana Turez. A reversedphase system consisting of a chemically bonded ODS silica gel column and 0.025 mol·L^-1 sodiumdihydrogen phosphate──methanol(35 :65)containing 0.1%sodium dodecyl sulphate(pH 8.0 as themobile phase was used.The four alkaloids were completely separated within 30 min. The analyticalresults for various samples were presented.