Display panel and preparation method thereof, display device and tiled display device

The embodiment of the invention provides a display panel and a preparation method thereof, a display device and a tiled display device, relates to the technical field of display, and is used for solving the problem that metal wires are easy to generate water and oxygen corrosion in the preparation process of the display panel. The display panel comprises a substrate, a plurality of connecting leads, a protective layer and an adapter layer. The substrate includes a first surface and a second surface opposite to each other, and a plurality of side surfaces connecting the first surface and the second surface. The plurality of side surfaces includes at least one selected side surface. The connecting lead comprises a first lead section located on the first surface, a second lead section located on the selected side surface, and a third lead section and a fourth lead section which are located on the second surface. The protective layer at least covers the side surfaces of the first lead section, the second lead section, the third lead section and the fourth lead section. The switching layer covers the surface, away from the substrate, of the fourth lead section and is electrically connected with the fourth lead section. The display panel is used for displaying images.