Abstract: An effective way that can distinguish the maturity of tobacco leaves and build a detection model of tobacco nicotine content using near infrared spectroscopy was explored. The NIR spectral date about 56 groups of tobacco leaves were analyzed by using clustering analysis, the classification results were almost the same as original, which reflected the difference between mature and immature tobacco leaves objectively. The rates of identification were up to 92.68%. A variety of spectroscopic processing methods were used to deal with the original spectrum. The method of multiplicative scatter correction (MSC) was better than others. Partial least squares regression (PLS) was used to established the regression model, which had the regression coefficient r=0.9852, RMSE=0.0676 in training set, r=0.9145, RMSE=0.1645 in cross validation set. The predicted values distributed closely in both sides of the fitting line, which showed a good result.