Display panel, preparation method thereof and display device

The invention discloses a display panel, a preparation method thereof and a display device, and belongs to the technical field of display. The display panel comprises a substrate, a first pixel defining layer and a second pixel defining layer. Through switching of the expansion part in the first pixel defining layer between the initial state and the expansion state, the distance between the side, away from the substrate, of the first pixel defining layer and the substrate can be increased or decreased. After the expansion part is in the initial state, the first ink can be used for forming light-emitting parts in different pixel holes. After the expansion part is in the expansion state, the second ink can be used for forming light-emitting parts in different pixel holes. Therefore, whether the first ink or the second ink is used for forming the light-emitting parts located in the different pixel holes, the thickness of the functional layers of the light-emitting parts which are located in the different pixel h