An array substrate, a display panel and a display device are provided. The array substrate includes: a substrate. A signal transmission line, first and second insulator layers, a pixel electrode layer and a common electrode layer are disposed on the substrate; wherein the signal transmission line, the first insulator layer and the second insulator layer are disposed between the common electrode layer and the pixel electrode layer, the signal transmission line is disposed on the first insulator layer, and the second insulator layer is disposed on the signal transmission line; and wherein a dielectric constant of the first insulator layer is less than or equal to a dielectric constant of the second insulator layer, and the signal transmission line is electrically connected with the common electrode layer. A parasitic capacitance between the signal transmission line and the common electrode layer is reduced in the array substrate.