A light emitting device and a manufacturing method thereof, and a display device are provided, which relate to the technical field of display. The light emitting device comprises a light emitting unit; an encapsulation layer on one side of the light emitting unit, the encapsulation layer including a reflective layer for reflecting first light; an adhesive layer located on one side of the encapsulation layer remote from the light emitting unit, the adhesive layer comprising an adhesive material capable of being cured by the first light; and a color film layer located on one side of the adhesivelayer remote from the encapsulation layer.