A method of fabricating an array substrate, an array substrate, and a display device is disclosed. The array substrate comprises a display area and a wiring area. The display area is disposed with a first thin film transistor and a second thin film transistor. A distance between a first active layer of the first thin film transistor and a substrate is different from a distance between a second active layer of the second thin film transistor and the substrate. The first thin film transistor comprises first vias that receive a first source/drain. The second thin film transistor includes second vias that receives a second source/drain. The wiring area is provided with a groove. The groove comprises a first sub-groove and a second sub-groove that are stacked. The method includes simultaneously forming the first vias and the first sub-groove, and simultaneously forming the second vias and the second sub-groove.