To optimize color rendering of mixed-color LEDs,the Gaussian model was used to analyze the color-mixed LED’s spectrum power distribution.The peak wavelength “λm”,spectral half width “Δλ” and amplitude “A” were basic parameters for optimizing color rendering R9,which is very important for objects to be colorful and vivid under the white light LED’s illuminating.The typical methods for color mixing were used to get white light LEDs.Result was that to get the satisfied color rendering index,one of the color primaries should be certain and then other color primaries would be analyzed through changing three basic parameters step by step.It was concluded that the analysis in this paper would be referential to optimize the color-mixed white LED’s color rendering.