A manufacturing method of a light-emitting substrate and a display device are provided. The manufacturing method includes: providing a substrate provided with a plurality of electrodes, forming a patterned photoresist layer including openings exposing the electrodes on a surface of the substrate, forming connecting parts in the openings, removing the patterned photoresist layer, and bonding a plurality of light-emitting elements on the connecting parts, wherein slope angles of a plurality of connecting part sidewalls of the connecting parts are ranged between 40° and 140°. The method could improve a yield rate of light-emitting elements bonded to electrodes through connecting parts.