OBJECTIVE:To establish an HPLC method for the assaying of silybin in Gantai capsule.METHODS:The assay was performed on Diamonsil C18 column.The mobile phase consisted of potassium dihydrogen phosphate solution-methanol(45:55)with a flow rate at 1.0ml/min,detection wavelength at 288nm,column temperature at(25?2)℃.The sample size was 20?l and the internal standard was kaempferol.RESULTS:There was a good linear relationship within the concentration range of 0.126～1.26 mg/ml(r=0.9 998)for silybin.The average recovery was 102.9%(RSD=1.50%).CONCLUSION:The method was simple,accurate and reproducible,and suitable for the assaying of silybin in Gantai capsule.