Preprocess method of multiplicative scatter correction (MSC) was used to reject noises in the original spectra produced by the environmental physical factor effectively,then the principal components of near-infrared spectroscopy were calculated by nonlinear iterative partial least squares (NIPALS) before building the back propagation artificial neural networks method(BP-ANN),and the numbers of principal components were calculated by the method of cross validation. The calculated principal components were used as the inputs of the artificial neural networks model,and the artificial neural networks model was used to find the relation between chlorophyll in winter wheat and reflective spectrum,which can predict the content of chlorophyll in winter wheat. The correlation coefficient (R) of calibration set was 0.960 4,while the standard deviation (SD) and relative standard deviation (RSD) was 0.187 and 5.18% respectively.The correlation coefficient (R) of predicted set was 0.9600,and the standard deviation (SD) and relative standard deviation (RSD) was 0.145 and 4.21% respectively. It means that the MSC-ANN algorithm can reject noises in the original spectra produced by the environmental physical factor effectively and set up an exact model to predict the contents of chlorophyll in living leaves veraciously to replace the classical method and meet the needs of fast analysis of agricultural products.