Liquid crystal display device and quantum dot LED are provided. The fluorescent layer is arranged at the light-emitting side of the LED chip so that the light of first wavelength generated by the LED chip excites the fluorescent layer to generate the light of second wavelength, the light of first wavelength excites the first quantum dot material of the quantum dot layer to generate the light of third wavelength, the light of first wavelength and the light of second wavelength excite the second quantum dot material to generate the light of fourth wavelength, the third wavelength is shorter than the second wavelength, and the light of third wavelength and the light of second wavelength have the same color.