A method of manufacturing a light-emitting element, and a light-emitting element array substrate and a display device including the same are provided. A method of manufacturing a light-emitting element includes: forming a base substrate including a plurality of protrusions and a rod area which is a remaining area except for the plurality of protrusions; forming a buffer layer on the base substrate; forming a semiconductor structure including a first semiconductor material layer, a light-emitting material layer, and a second semiconductor material layer on the buffer layer; forming a plurality of mask patterns overlapping the rod area on the semiconductor structure; forming element rods by removing the semiconductor structure overlapping the plurality of protrusions using the plurality of mask patterns; forming an insulating film around an outer surface of each of the element rods. and separating the element rods from the buffer layer.