An organic electroluminescent device, a method for manufacturing the same, and a display device. The organic electroluminescent device includes: a base substrate comprising a plurality of pixel regions thereon; a pixel electrode layer; a planarization layer, formed with a protrusion on a surface of the planarization layer facing away from the base substrate and at a position corresponding to at least one side edge of a periphery of each pixel region; an anode layer, the anode layer being electrically connected to the pixel electrode layer through a via hole, and the anode layer covering the pixel region and covering a side surface of the protrusion facing the pixel region; a light emitting layer, a height of a surface of the light emitting layer being less than a height of the anode layer covering the side surface of the protrusion; a pixel definition layer; and a cathode layer.