White light emitting diodes (LED) are packaged based on blue LED dies surrounded by two different phosphors that emit red and green light respectively. First, the ratio of two phosphors maintains invariable, color rendering index achieves the maximal value in some color temperature, when it increases from 2700 K to 13000 K by degrees. Then, the ratio of two phosphors is changed gradually, by repeating above test, it is found that the color temperature corresponding to the maximal color rendering index is different at different phosphors ratio. The experimental results indicate that color rendering index can reach above 90 in any color temperature region from 2700 to 13000 K by matching the ratio of red, green phosphors and silica gel. Especially, color rendering index can achieve about 96 in the color temperature below 4000 K. Therefore, the maximal color rendering index in any color temperature can be obtained by the choice and match between blue LED dies, excitating and emitting wavelength, and the scale between them.