An array substrate and a manufacturing method thereof, a flexible display panel and a display device are provided. The array substrate includes a flexible substrate divided into a display region and a periphery region, the periphery region surrounding the display region. The array substrate further includes: an array layer and a first film layer sequentially formed in the display region on the flexible substrate; a plurality of integrate circuits and a flexible printed circuit board interface formed in the periphery region on the flexible substrate; a flexible protective film layer formed on a junction of the periphery region and the first film layer and in a region of the periphery region other than the integrate circuits and the flexible printed circuit board interface on the flexible substrate.