Preparation method for QLED and preparation method for QLED display device

The invention provides a preparation method for a QLED (Quantum-dot Light Emitting Diode). The preparation method for a QLED comprises the steps: 1 providing an anode; 2 providing a mixed solution containing quantum dot luminescent materials and cavity transmission materials, wherein the mixed solution includes a first solvent and a second solvent; the solubility of the first solvent to the quantum dot luminescent materials is greater than 10mg/ml; the solubility of the first solvent to the cavity transmission materials is less than 0.1mg/ml; the boiling point of the first solvent is greater than 200DEG C; and the boiling point of the second solvent is less than 150DEG C; 3 printing the mixed solution on the anode and forming a semi-solidified mixed film; 4 coating the surface of the semi-solidified mixed film with a third solvent to enable the semi-solidified mixed film to form the successively stacked cavity transmission layer and quantum dot luminescent layer on the anode, wherein the boiling point of the third solvent is less than 100DEG C, and the third solvent and the first solvent are mutually soluble, and do not dissolve the cavity transmission materials; and 5 depositing a cathode on the quantum dot luminescent layer.