Objective: To realize quality control of water extracting process,near-infrared (NIR) spectroscopy was used to establish a rapid quantitative analysis model for the content of gastrodin and total solid content in the second water extracting process of Tianshu capsules,which could timely reflect its state. Method: Samples of the second water extracting process of Tianshu capsules were collected,after rejection of abnormal samples,pretreatment of spectra and choice of corresponding wave band,multivariate calibration models were respectively established by partial least squares (PLS) algorithm between spectra and the content of gastrodin or total solid content.Samples in the concentrating process,which did not participate in modeling were used to test performance of models. Result: Correlation coefficients of the content of gastrodin and total solid content were 0.9680 and 0.9772;predicted coefficients of them were 0.9659 and 0.9786,root mean square error of calibration (RMSEC) were 4.686 and 0.053,root mean square error of prediction (RMSEP) were 3.698 and 0.034,and the relative standard errors of predictions (RSEP) were 4.85% and 3.07%,respectively. Conclusion: The method mentioned above is proved to be convenient,rapid,accurate and applicable for fast analysis and monitoring of active components in the second water extraction process of Tianshu capsules.