Abstract: The holocellulose is one of the main chemical components of wood cell wall and has a critical effect on wood property andutilization. The holocellulose contents of 42 samples of poplar were determined by national standard of China, and then the near infrared (NIR) of all samples was collected by LabSpec Pro FR/ A114260 in this paper. The calibration and validation model were built using partial least squares (PLS1, PLS2) and principal component analysis (PCR) with different pretreatment methods of un- pretreatment, Baseline, the first derivative and the second derivative in different spectral regions of 350- 2 500 nm, 1 300-2 050 nm and 2 050-2 500 nm. The results showed that the best model was built by PLS1 with un-pretreated spectral data and 8 principal components in 1 300-2 050 nm. The coefficients of correlation (r), the root mean square error and the standard error of calibration model were 0.963 8, 0.006 3 and 0.006 4, respectively, and 0.647 1, 0.023 6 and 0.024 0 for validation model. The correlation (r) was 0.818 8 between the predicting and lab measuring values of the samples not involved in modeling.