Disclosed are a display substrate, an organic light-emitting diode display panel and a display device. The display substrate includes a base substrate and a pixel defining layer located on a side of the base substrate, wherein the pixel defining layer is provided with a plurality of sub-pixel openings, outer contour shapes and sizes of all the sub-pixel openings are the same, filling parts are arranged in at least parts of the sub-pixel openings, and for different sub-pixel openings, area ratios of the filling parts to the sub-pixel openings are different.