Objective: To determine the content of saikosaponin A in Radix Bupleuri by combining near-infrared spectroscopy with the chemometrics method. Method: The content of saikosaponin A in Radix Bupleu was determined by HPLC as a reference method. Multivariate calibration model based on PLS algorithm was developed to correlate the spectra and the corresponding values determined by the reference method. Result: RMSECV (root-mean-square error of cross-validation)of the model for saikosaponin A was 0.321 and the correlation coefficients of the calibration model was 0.934.External validation proved that the relative coefficient of the predicted value and the HPLC value was 0.951

with measured recycle rate of 96.64%. Conclusion: NIRS can be used in the determination of saikosaponin A

which sets up the foundation of product-line control of Radix Bupleuri.