The disclosure provides an organic light-emitting device, a fabrication method thereof, and a display device. The organic light-emitting device comprises an anode layer, a cathode layer, and an organic function layer disposed between the anode layer and the cathode layer. The organic function layer comprises a light-emitting layer. The light-emitting layer comprises a first sub light-emitting layer and a second sub light-emitting layer disposed adjacent to each other, the first sub light-emitting layer is provided on an anode layer side and the second sub light-emitting layer is provided on a cathode layer side. The first sub light-emitting layer and the second sub light-emitting layer have a substantially same energy band difference, and one of the first sub light-emitting layer and the second sub light-emitting layer is capable of absorbing light emitted by the other of the first sub light-emitting layer and the second sub light-emitting layer to achieve stimulated emission.