The excitation spectrum of white LED is studied in this paper.Here,the DCJTB was mixed into YAG phosphor by the proportions of 1%,2%,5% and 10%,respectively.With the mixing concentration increasing,we find that there are significant excitation peaks in the red and yellow regions(550 nm~750 nm).And spectral color coordinates move from white region(0.269 5,0.243 5) to red region(0.447 9,0.272 9).However,the spectral peak in green region is nearly decreased to zero.So the spectrum shows two relatively independent peaks.The color-rendering index of LED reaches the maximum of 74.2 when the mixing concentration is 1%.However,with the increase of mixing concentration,the color index decreases clearly.Therefore,the energy emitted from LED chip can stimulate DCJTB.Meanwhile,the DCJTB has a strong absorption in the green region excited by the YAG phosphor.