The present invention provides a flexible display substrate, the manufacturing method thereof and a flexible display device, relates to the field of flexible display technology, and can solve the technical problems that the existing flexible display substrate is easy to be damaged during deforming, has small amount of deformation, degraded display performance or high costs, or has difficulty in manufacturing process. The flexible display substrate according to the present invention comprising a hard material layer disposed at the fragile positions of the flexible display substrate. The manufacturing method for the flexible display substrate according to the present invention comprises forming a pattern of a hard material layer. The flexible display device of the present invention comprises the flexible display substrate mentioned above. The present invention is applicable to flexible display devices such as flexible organic electroluminescent display device, flexible electrophoretic display device, or liquid crystal display device.