The invention is intended to provide a wavelength conversion device, comprising a base plate, a diffuse reflection layer positioned on the base plate, and a light-emitting layer positioned on the diffuse reflection layer, wherein the light-emitting layer is used for receiving irradiation of exciting light and converting the exciting light into excited light differed from the exciting light in wavelength, and the diffuse reflection layer is used for reflecting the exciting light and excited light which penetrate the light-emitting layer, wherein first phosphor particles are pacakaged in the light-emitting layer via organosilicone glue, and wherein the diffuse reflection layer contains a mixture of first glass powder and diffuse reflection particles.