The invention provides an array substrate, a fabrication method thereof and a display device. By improving a structure of a thin film transistor, the overlapped regional area between a data line and agate line can be reduced, the unfavorable problem of display such as crosstalk and flicker caused by overlapping of the data line and the gate line is effectively improved, and the risk that the dataline is open can be effectively reduced. The array substrate comprises a substrate, a gate line, a data line and a thin film transistor, wherein the gate line and the data line are arranged above thesubstrate in a staggered way, the thin film transistor comprises a gate, an active layer, a source and a drain, the active layer is arranged at one side, far away from the substrate, of the gate, thesource and the drain are arranged at one side, far away from the substrate, of the active layer, the gate is a part of the gate line, the source is a part of the data line, and at least one part of region of the source is arranged in a region where positive projections of the data line and the gate line on the substrate are overlapped.