The objective of the present study was to develop a method for the determination of sinigrin in semen Thlaspi from Sichuan using near infrared diffuse reflectance spectroscopy. Near infrared spectra (NIR) in the region of 7 502.1-5 446.2 cm^-1 were recorded for the 246 semen Thlaspi samples containing sinigrin in the content of 1. 962%-3. 917%. Calibration models were established using the PLS (partial least squares). Different spectra pretreatment methods were compared. The study showed that spectral information can be extracted thoroughly by minimum and maximum normalization pretreatment methods. In this calibration model, the correlation coefficient (R^2) was 0. 928 0, the SEC (standard deviation of the calibration sets) was 0. 314 and the SEP (standard deviation of the prediction sets) was 0. 388. Results indicated that near infrared diffuse reflectance spectroscopy method can be used to rapidly analyze the valid component in traditional Chinese medicine, and also can be used in the quality control of traditional Chinese medicine.