The invention relates to the technical field of display, in particular to a light-emitting device and a preparation method thereof, and an organic electroluminescent display comprising the light-emitting device. A layer of electron capture layer is inserted into the hole transport layer, and/or a cavity capture layer is inserted in an electron capture layer, so that electrons and/or cavities whichleak from the light emitting layer release energy in a radiation transition mode, and material aging caused by heat release caused by non-radiation transition is avoided. The service life of the device can be effectively prolonged.