In this paper, the emission spectra of a high color rendering phosphors, mixed with the Yttrium Aluminium Garnet, Silicon based Oxynitride and Nitride based phosphors, were predicted by using the Lambert-Beer theory and Back Propagation Neural Network (BP NN). Firstly, the modified Lambert-Beer model was used to calculate the proportional coefficient of the emission spectra of the mixed phosphors in ratios. Next, the BP NN was implemented to train and predict the proportional coefficients. Finally, the prediction of the emission spectra of the mixed phosphors were estimated and verified by the experimental measurements. The results show that: (1) The prediction error percentage of the scale factor can be controlled within 5%; (2) The predicted emission spectra by BP NN keep high agreement with the experimental measurements with lower RMSE andΔxy as 0.019 and 0.0016, respectively.