Embodiments of the invention provide a supporting plate, a touch display panel and a touch display device. The supporting plate is used in a touch display panel, which includes a touch screen and a display panel. The supporting plate is arranged between the touch screen and the display panel in a region corresponding to a non-active area of the touch display panel, and includes a supporting part used for supporting the touch screen, wherein at least part of the top surface of the supporting part is fixedly connected to the touch screen, and the top surface of the supporting part is not higher than the top surface of the touch screen to be fixed, so as to expose the entire top surface of the touch screen. According to embodiments of the invention, assembling of the touch screen is easier and design of narrow or no bezel can be achieved.