A flexible display panel, a manufacturing method thereof and a display device are disclosed. The flexible display panel includes a first flexible substrate and a second flexible substrate which are cell-assembled with each other; and a liquid crystal display layer, a black matrix grid and a plurality of polymer walls which are located between the first flexible substrate and the second flexible substrate; the liquid crystal display layer is located in gaps of the plurality of polymer walls, and includes a plurality of liquid crystal pixel units arranged in an array; the plurality of liquid crystal pixel units are delimited by a projection of the black matrix grid on the liquid crystal display layer.