A manufacturing method of a display substrate, a display substrate, and a display device. The manufacturing method includes: forming an active layer; forming a gate insulation film layer, a gate film layer and a photoresist film layer; exposing the photoresist film layer to a light and developing the exposed photoresist film layer until the developed photoresist film layer has a thickness of 1.8-2.2 μm and a slope angle not less than 70°; over-etching the gate film layer to form a gate electrode, an orthographic projection of the gate electrode being located within a region of an orthographic projection of the developed photoresist film layer; over-etching the gate insulation film layer by a gaseous corrosion method to form a gate insulation layer; peeling off the photoresist film layer remaining on a surface of the gate electrode; and performing a conductive treatment to the active layer.