Display panel, preparation method thereof and display device

The embodiment of the invention discloses a display panel, a preparation method thereof and a display device. The display panel comprises a substrate, a first water vapor barrier layer, an OLED devicelayer and a second water vapor barrier layer, wherein the second water vapor barrier layer comprises a first inorganic layer and a buffer stress layer which are stacked, the buffer stress layer is located on the side, which is away from the substrate, of the first inorganic layer, the first inorganic layer and the first water vapor barrier layer wrap the OLED device layer, the buffer stress layerand the first water vapor barrier layer wrap the OLED device layer, the buffer stress layer comprises a buffer part, and the buffer part is embedded into the first inorganic layer. According to the technical scheme provided by the embodiment of the invention, the light-emitting unit is wrapped by the first water vapor barrier layer and the second water vapor barrier layer to form a double-layer sealed packaging structure,