Objective: To develop a novel method for fast analysis of one active component in water extracting process of Paeonia lactiflora with near infrared transmittance spectroscopy. Method: The calibration model of 54 extraction samples was developed by the spectral data pretreatment of the multiplicative scatter correction (MSC) with the spectral regions (6 101.9-5 446.2

4 601.5-4 424.1 cm-1) and analyzed the correlation between the spectra and the corresponding values by PLS method. Result: The R2was 0.998 9

the root mean square error of Cross-Validation (RMSECV) was 0.025 2 and the best dimension was six. The paeoniflorin in the 13 samples was evaluated by using the model established

root mean square errors of prediction(RMSEP)was 0.086 1. Conclusion: This method is not only rapid

simple

accurate and reliable

but also has great application prospects in the optimization of extraction technology and on-line monitoring of production process in TCM field.