The near infrared reflectance spectroscopy (NIRS) and partial least square regression (PLS) were used to establish the models by comparing several preprocessing procedures and wavelength ranges. The optimal models could be obtained in the range of 6101.7 similar to 5773.8 cm(-1) and 4601.3 similar to 4246.5 cm(-1) by the spectral data preprocessing of the second derivative. In addition, 15 additional maize stalk samples were used to evaluate the reliability. of the calibration model. The corelation coefficient was 0.9953 between NIRS predicted and actual cellulose in these materials. Thus, the accuracy of prediction could be comparable to that of chemical method. The results show that NIRS is a simple effective means for measuring cellulose in maize stalk. The results are of great important in screening and evaluating quality constituents of silage maize.