Two kinds of high color rendering index light emitting diode (LED) are made by yellow, red phosphor and yellow, red, green phosphor respectively. The light output of the sample with green phosphor is bigger due to more green light in spectrum after the addition of green phosphor and the larger vision function of green light than that of red light. The luminous efficiency decreases and color rendering index increases when the testing temperature varies from 10 ℃ to 90 ℃. This suggests that, besides the degradation of internal quantum efficiency, the mismatch of red shift of wavelength of the chip and the excitation wavelength of phosphor and the degradation of excitation efficiency of phosphor at high temperature are all the reasons of degradation of luminous efficiency. The color rendering index increases due to wider spectrum of blue light emitted by the chip at high temperature which makes the spectrum smoother and closer to the spectrum of the sun.