RÉSUMÉ
OBJECTIVE：To establish the method for online rapid detection of related indexes in the concentration process of Huagai san extraction solution ，and to provide reference for judgment of concentration end point. METHODS ：Online diagram of 73 concentrated samples in the concentration process of Huagai san extraction solution were drawn by NIRS online collection equipment. The partial least squares （PLS）method was used to establish the NIRS quantitative calibration model of 5 related indexes （concentration density ， solid content ， the contents of amygdalin ， ephedrine hydrochloride and pseudoephedrine hydrochloride）. Another 15 samples were used to validate the model ，and the correlation of predicted value and measured value was analyzed. RESULTS ：The correlation coefficients （R2）of the concentration density ，solid content ，the contents of amygdalin ， ephedrine hydrochloride and pseudoephedrine hydrochloride in the quantitative calibration model were 0.982 5，0.999 9，0.998 3， 0.999 4 and 0.999 3，respectively；the root mean square errors of calibration （RMSEC）were 0.001 6，0.025 1，0.014 7，0.001 8 and 0.000 9；the root mean square errors of cross validation （RMSECV）were 0.002 1，0.035 8，0.033 6，0.006 3 and 0.001 3， respectively. After validation by 15 samples，root mean square errors of prediction （RMSEP）were 0.003 2，0.024 6，0.021 5， 0.007 7 and 0.005 9，respectively. CONCLUSIONS ：The established quantitative calibration model has good predictability and can provide basis for online judgment of concentration end point of Huagai san extraction solution.