Manufacturing method of display substrate, display substrate and display device

A manufacturing method of a display substrate, comprising manufacturing a top-gate type thin film transistor on a side of a base substrate, wherein manufacturing the top-gate type thin film transistor on the side of the base substrate comprises:

• forming an active layer;
• forming a gate insulation film layer, a gate film layer and a photoresist film layer sequentially on a side of the active layer away from the base substrate;
• exposing the photoresist film layer to a light using a mask as a protection mask, 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 that is not less than 70°;
• over-etching the gate film layer to form a gate electrode using the developed photoresist film layer as a protection mask, an orthographic projection of the gate electrode on the base substrate being located within a region of an orthographic projection of the developed photoresist film layer on the base substrate;
• over-etching the gate insulation film layer by a gaseous corrosion method to form a gate insulation layer using the developed photoresist film layer as a protection mask;
• peeling off the photoresist film layer remaining on a surface of the gate electrode;
• and
• performing a conductive treatment to the active layer using the gate insulation layer as a protection mask.