Objective: To establish a new method for rapidly determining the water content in Arisaematis Rhizoma using near-infrared (NIR) spectroscopy. Method: The water content in Arisaematis Rhizoma was determined by the oven drying method

and the multivariate calibration model between the measured content and the NIR spectrum was established by the partial least square (PLS) regression method. The established model was optimized and evaluated using the correlation coefficient (R)

the root-mean-square error of calibration (RMSEC)

the root mean square of cross-validation (RMSECV) and the root mean square of prediction (RMSEP). The accuracy of the calibration model was tested by comparing the predicted values and the measured values of the water contents in samples of the prediction model. Result: The NIR spectra were processed by the second derivative spectrophotometry

and the optimal spectral intervals for establishing model ranged between 4 774-9 845 cm-1

and six optimal principle components were included. Under the optimal conditions

the quantitative calibration model was established

with R of 0.990 6

RMSEC of 0.16 and RMSECV of 0.38.According to the external validation

the RMSEP and average recovery of the calibration model were 0.298 and 99.8%

respectively. Conclusion: The near-infrared spectroscopy quantitative model established in this study is stable

accurate and reliable for the rapid determination of the water content in Arisaematis Rhizoma.