Cover plate and preparation method thereof, display panel and display device

The embodiment of the invention discloses a cover plate and a preparation method thereof, a display panel and a display device. The cover plate is used for the OLED display panel and comprises a coverplate body, an electric curtain layer and a protective film, wherein the electric curtain layer and the protective film are sequentially arranged on the light emitting side of the cover plate body ina stacked mode. According to the cover plate of the embodiment, through cooperation between the electric curtain layer and the protective film, the electric curtain layer is used for generating an electric field to lift up dust particles on the adsorption surface and continuously move till the dust particles are moved out of the adsorption surface, and therefore the effect of carrying dust in a non-contact mode is achieved; therefore, the light transmittance of the back plate and the display effect of the display device loaded with the cover plate are improved. 本申请实施例公开一种盖板及其制备方法、显示面板和显示装置。该盖板用于OLED显示面板，该盖板包括盖板本体及依次层叠