The present invention discloses an array substrate, a display panel and a display device. The array substrate includes a substrate, a gate line and a data line arranged on the substrate, and a thin film transistor arranged in an overlapping region where the gate line and the data line are overlapped; wherein an orthogonal projection of the thin film transistor on the substrate covers an orthogonal projection of the overlapping region of the gate line and the data line on the substrate. Because of design of a location of the thin film transistor according to the present invention, the opening ratio can be increased, the slightly rubbing region adjacent to the thin film transistor can be reduced; and, because of the closed channel region, levels at various positions of the thin film transistor can be uniform, and a bigger contact area provided for the supporting post, thereby increasing supporting ability of the supporting post and compressive property of the panel.