A flexible display module and a manufacturing method thereof are disclosed. The flexible display module includes a first flexible material layer and a second flexible material layer stacked on the first flexible layer, a sealing layer disposed between the first flexible material layer and the second flexible material layer, and a module layer disposed in the hollow of the sealing layer. The sealing layer has a hollow defined in a middle of the sealing layer. The area of the bottom area of the hollow is larger than the area of the module layer.