The present disclosure provides a flexible display substrate and a manufacturing method therefor, and a display apparatus. The flexible display substrate includes: a flexible substrate, a display function layer at a side of the flexible substrate, a film packaging layer at a side of the display function layer facing away from the flexible substrate, and a leveling layer at a side of the film packaging layer facing away from the flexible substrate, where the flexible substrate includes a non-bending area and a bending area, the leveling layer is at least located in the bending area, and the leveling layer is configured to compensate for a height difference between a related film layer structure in the non-bending area and a related film layer structure in the bending area.