The present invention provides a QLED device of a quantum well level structure. The QLED device comprises a substrate, a bottom electrode, a hole injection layer, a hole transmission layer, a quantum dot luminescent layer, an electron transferring layer and a top electrode which are laminated and arranged in order; the quantum dot luminescent layer is a quantum well level structure and includes a first band gap layer and a second band gap layer which are alternatively laminated in order, and two surface layers of the quantum dot luminescent layer are both the first band gap layers; and the first band gap is made by the first band gap materials, the second band gap layer is made of the quantum dot luminescent materials, and the band gap width of the first band gap materials is larger than the band gap width of the second band gap materials, wherein the energy level difference between the two is not less than 0.5eV.