The present invention discloses a quantum dot luminescent layer and device, and preparation methods thereof, a luminescence module and a display device. The preparation method of the quantum dot luminescent layer comprises the steps: the quantum dots having the surfaces coated with ligand are dissolved in solvent to obtain the quantum dot solution; the quantum dot solution is deposited on the substrate or a function layer by employing the solution method to obtain a quantum dot luminescent layer; the quantum dot luminescent layer is arranged in a vacuum cavity, and organic metal compounds are pumped in to process for 0.5-30 mins, wherein the pressure in the cavity is 0.01-1mbar, the partial pressure of the organic metal compounds after gasification is 0.001-0.1mbar, the temperature in the cavity is 10-25 DEG C; and the quantum dot luminescent layer is taken out to obtain the quantum dot crosslinking luminescent layer. The quantum dot film is not only uniform flat and has a stable film, so that the quantum dot film is difficult to be redissolved to take away or wash away by the solvent when the subsequent other function layers are deposited so as to effectively improve the luminescence uniformity and the stability of the QLED.