A white-light emitting device comprises a substrate, a short wavelength light source, a protective layer, a first structure, and a second structure. The short wavelength light source is disposed on the substrate for generating a first light, and the protective layer covering the short wavelength light source is pervious to the first light. The first structure is disposed on the protective layer for generating a second light, in which the first structure includes a first quantum well and a transmission layer. The second structure is disposed on the first structure for generating a third light. Finally, the first light, the second light, and the third light are mixed to generate a white light.