Abstract:A high performance liquid chromatographic method for the determination of saikosaponin a,c and d in Radix Bupleuri was developed. YMC-pack A-314 ODS column (6×300mm) with an eluent consisting of acetone-water (58:42)at a flow rate of 1.2ml/min was used. The saikosapo mins wore monitored by a differential refractometer without being converted into thecorreaponding diane dorivatives in advance. Megestrol was used as the internal standard. The recovery rats of saikosuponins was higher than 95% and the coefficient of variation (CV)was 3.08%. The contents of saikosaponins a. c and d of 13 species of Radix Bupleuri collected in different districts of China wore evaluated by this method.