Embodiments of the present disclosure provide a display substrate and a display device. The display substrate includes: a base substrate; a pixel defining layer, located at a side of the base substrate and having pixel openings emitting light of different colors, wherein the pixel opening has a pixel opening orthographic projection; and a black matrix, located at a side of the pixel defining layer away from the base substrate and including black matrix openings corresponding to the pixel openings, wherein the black matrix opening has a black matrix opening orthographic projection covering the corresponding pixel opening orthographic projection, and the black matrix opening has an opening expansion with relative to the pixel opening; at positions of at least two pixel openings with different light-emitting colors, in a same direction parallel to the base substrate, the opening expansion is inversely proportional to a length of the pixel opening orthographic projection.