Abstract Based on partial least squares, the dimethyl monomethyme content was measured. The original spectroscopy, smooth, first-order differential, second-order differential, multi-scattered correction, standard regular conversion, the main cause of the child were effectively used. The results show that the model performance of 6 main factors established separately, the correction set coefficient and verification set coefficient of correction set is 0.9999 and 0.9991, respectively, and the correlation set prediction standard deviation is 0.00356, respectively. And 0.0178. This optimal model is used to measure the blind sample of modeling. As a result, the deviation of the measurement results is between -0.028% ∼ 0.012%, the average deviation is from 0.014%, the standard deviation is 0.014%, and the relative standard deviation is 2.9%. The result is satisfactory.