The embodiment of the invention provides an potential fault excitation and detection method for an array substrate, a display panel and a display device. The array substrate comprises a grid driving area, the grid driving area is provided with a grid driving circuit, the grid driving circuit comprises a plurality of cascaded shift register units, and each shift register unit comprises a first detection point, a second detection point and a sub-circuit connected between the first detection point and the second detection point. The fault excitation method provided by the embodiment of the invention comprises the steps of setting a voltage difference between a first detection point and a second detection point as a preset voltage difference within a preset time length, if a sub-circuit does not have a potential fault, not conducting the sub-circuit, and if the sub-circuit has the potential fault, exciting the potential fault as an actual fault under the action of the preset voltage difference. According to the embodiment, the array substrate with a potential fault can be prevented from entering a subsequent process, so that the production cost is reduced, and the yield is improved; and the array substrate can be prevented from being damaged by the voltage applied between the two detection points.