An organic-light-emitting-diode device and a fabricating method thereof, a displaying base plate and a displaying device, wherein the organic-light-emitting-diode device includes a substrate, and an anode layer, an organic functional layer and a cathode layer that are provided in stacking on one side of the substrate, wherein the organic functional layer includes a first functional layer, a second functional layer and a light emitting layer that are provided in stacking, and the first functional layer is provided closer to the anode layer; and a HOMO energy level of the second functional layer is deeper than both of a HOMO energy level of the first functional layer and a HOMO energy level of a host material of the light emitting layer.