In order to effectively simulate the luminescence spectrum of two kinds of phosphor mixed coated white LEDs, the silicate series of green phosphors and high-viscosity series of red phosphors were selected. Fluorescence spectra of green phosphors and red phosphors were measured by the British FLS920P fluorescence spectrometer. The emission peak of green phosphor was 527 nm and the emission peak of red phosphor was 641 nm. Totally, there were 144 samples, which have a concentration ranging from 7% to 17% and a proportion of 3∶1 to 3∶2. The HAAS-2000 high-precision spectroradiometer from Hangzhou Yuanfang Spectrum Co., Ltd. was used to measure the LED luminescence spectrum. Finally, the data were processed to obtain the fitting function. Based on these functions, the spectral equation was constructed. This spectral equation is a systematic method of simulating the concentration and proportion of two phosphors. In order to accurately predict the luminescence spectrum of the two kinds of phosphors mixed and applied to the blue chip, a three-dimensional surface fitting was performed on the data in the experiment, and the relationship between the concentration and proportion of the phosphor and the green correction coefficient and the red correction coefficient was obtained. Applying the obtained functional relationship between the green correction coefficient and the red correction coefficient to the spectral equation, a new method for finally simulating the luminescence spectrum of white LEDs was obtained. Moreover, the simulated spectra of the two groups were compared with the actual experimental spectra, and the results of the two spectra were found to be good. This new method of simulating white LEDs is indeed feasible, and the predicted phosphorescence spectra of the two phosphors coated on the blue chip are more accurate. This method relates the specific phosphor mass ratio and concentration to the luminescence spectrum of the LED, and most previous studies have linked the spectral power distribution to the LED luminescence spectrum, the mass ratio and concentration of the phosphor are not involved, and the specific breakthrough is compared. After the specific spectral equation is established, the final simulated white light spectrum can be directly obtained according to the mass proportion of the two phosphors and the concentration after mixed with the AB glue without the experimental instrument and without the actual experiment. Get rid of the limitations of experimental instruments and other factors. And it provides a new idea for the preparation of white LED with specific spectral characteristics, which has certain practical value.