A flexible display panel and a manufacturing method thereof are provided. The flexible display panel includes a display region and a non-display region. A part of the flexible display panel disposed in the non-display region includes a flexible substrate, a multi-barrier layer, and a planarization layer. A cutting track is defined at a peripheral edge of the non-display region, and a groove is defined in the cutting track. An end of the planarization layer extends to at least an interface formed between the multi-barrier layer and the flexible substrate through a sidewall of the groove.