Abstract: In order to improve the domestic pulp output and utilization rate, and alleviate the shortage of high-quality materials in the pulping and paper-making industry, a rapid analysis research was conducted on the specific material model of pulp making-Eucalyptus-Acacia mixed with pulpwood in southern China. The near-infrared spectra of 175 Eucalyptus-Acacia mixed samples and 45 single-species samples were collected. The mixing degree and chemical composition content of all samples were analyzed. The original spectra were preprocessed by the combined pretreatment methods of smoothing, vector normalization(V-Norm), multiple scattering correction(MSC), first derivative(1st Der) and second derivative(2nd Der). Combined with the least absolute shrinkage and selection operator(LASSO) algorithm, the mixing degree, holocellulose, Klason lignin, pentosan, benzene-alcohol extractives and 1% NaOH extractives content models were built. The optimal adjustment parameters determined during the modeling process were 13.62, 18.30, 6.39, 9.64, 7.49, and 12.07. The RMSEP values of the six models were 1.93%, 0.61%, 0.51%, 0.80%, 0.28%, and 0.41%, respectively. The absolute deviation ranges were -3.19%-3.24%, -0.96%-1.01%, -0.89%-0.84%, -1.37%-1.46%, -0.43%-0.39%, -0.58%-0.60%. The models have good adaptability and could meet the needs of the pulping and paper-making industry. It also confirmed the feasibility of the LASSO algorithm for the analysis of mixed pulpwood materials.