A display substrate, a display panel including the display substrate and a display device including the display panel are provided. The display substrate comprises a flexible circuit board and test pads, wherein the flexible circuit board covers an area of the test pads. In the aforesaid display substrate, the flexible circuit board covers the area of the test pads, so that test points on the test pads can be prevented from contacting the outside, and corrosion of the test points and signal abnormity in signal lines resulting therefrom during testing are prevented; compared with the prior art, the process of coating the test pads with UV adhesive is omitted, thus the process flow is reduced, and the production efficiency and the productivity are improved; moreover, the thickness of the display substrate can be reduced, which is conducive for the display panel including the display substrate to be lighter and thinner.