The invention provides a flexible display substrate, a fabrication method thereof and a display device, and belongs to the technical field of display. A wiring region (comprising a bending region) ofthe flexible display substrate is not covered by a planarization layer, protection films at least cover an upper surface and a side wall of a conductive pattern on the wiring region of the flexible display substrate, and the corrosion of an etching liquid to the conductive pattern can be prevented by the conductive pattern. With the flexible display substrate provided by the technical scheme, theyield of the display device can be improved.