Objective: To compare the contents of saikosaponin a, d and total flavonoids in different parts of Hollow bupleurum to provide reference for the clinical use of medicinal parts.Methods: The determination was performed on a SHIMADZU Inertsil C18(250 mm×4.6 mm,5 μm)column.The mobile phase consisted of acetonitrile and water with the ratio of 40∶60, and the flow rate was 1.0 ml·min-1.The detection wavelength was 210nm, the column temperature was 40℃, and the injection volume was 10 μl.A colorimetric method was used to detect total flavonoids with the detection wavelength of 500 nm.Results: The calibration curve of Saikosaponin a, d and total flavonoids showed a good linear relationship respectively over the range of 0.21-1.26 mg·ml-1(r=0.999 6),0.25-1.51 mg·ml-1(r=0.9997) and 4.00-25.00 μg·ml-1(r=0.999 6).The average recovery was 99.27%(RSD=2.15%, n=6),99.4%(RSD=2.14%,n=6)and 99.03%(RSD=1.34%,n=6), respectively.The content of saikosaponin a and d respectively was 0.31% and 0.50% in the root, while that in the other parts was low.The content of total flavonoids was as high as 8.48% in flowers, and that in leaves, stem and root reduced in turn.Conclusion: The aerial parts of Hollow bupleurum are rich in flavonoids, and the content of saikosaponin in root is higher, therefore, the whole plant with root is more reasonable in the clinical use.