This invention relates to the technical field of electronic components, and in particular to an improved illuminating device of light emitting diode (LED) wafer holder. The improved illuminating device of LED wafer holder comprises a reflecting shade and a diode crystal holder, wherein the diode crystal holder comprises a plurality of electrode portions and isolation portions disposed between the electrode portions; a plurality of crystals are disposed on the upper end of the electrode portion; a connecting piece with functions of radiation and conduction is fixedly set between one crystal and another; the diode crystal holder is connected with three non-polar brackets; the reflecting shade is internally provided with a plastic sheet which is opened with air holes; the inner wall of the plastic sheet is provided with fluorescent powder. This invention arranges the connecting piece between one crystal and another by means of the principle of mechanical structure to replace the conventional lead welding; furthermore, due to the air holes opened on the plastic sheet inside the reflecting shade, the deterioration of fluorescent powder and silica gel can be avoided, the problems of light source attenuation, lead floating and lead short circuit can be overcome and the service life can be extended.