A method of thinning a display panel and a display device are provided, to solve the technical issue in the related art that a color filter substrate of an ultrathin display panel is of a lower strength if the color filter substrate is too thin. According to the method of thinning the display panel, the intermediate layer is coated onto the surface of the first substrate away from the second substrate, the protection adhesive is attached on the intermediate layer, and the second substrate is chemically thinned at one side thereof, thereby protecting the first substrate from being chemically thinned during the chemical thinning.