In the present paper the polysaccharides in Ophiopogon japonicus was analysed quantitatively by using near infrared spectroscopy. The spectral characteristics of the primary ingredients in ophiopogonis were obtained by applying first derivative, second derivative, smoothing,SNV (standard normal variate), and MSC (multiple scatter correction), and the wavelengths were selected for the best model. Meantime, in combination with the PLS algorithm the calibration process was performed for the quantitative analysis of the polysaccharides in Ophiopogonjaponicus. The result showed that after optimizing all the factors, the best model of equation was using ＂first derivative＂+＂MSC＂+＂SG＂, and the wavelengths for the best model were selected in 4 000-4 900, 5 100-6 900 and 7 050-10 000 cm^-1. The result showed a fine precision of the method, with R^2, RMSEC, R^2cv, RMSECV and principal factors being 0. 996, 0. 237, 0. 973, 0. 583 and 6, respectively. A set of representative samples were used to check the model, and the prediction coefficient of determination was 96.88%.