A display panel, a manufacturing method and a display device are provided. The display panel includes a substrate having a display area and a non-display area; a planarization layer covering the display area and the non-display area of the substrate; an organic light emitting element located in the display area and located at a side of the planarization layer away from the substrate; an encapsulation structure including a first inorganic layer, an organic layer and a second inorganic layer which are sequentially stacked, where the first inorganic layer and the second inorganic layer extend into a non-display area, and the first inorganic layer is arranged close to the planarization layer; and/or, a part of the planarization layer located in the non-display area is provided with a groove, and the groove is filled with a flexible water-oxidation resistant material.