Disclosed are an array substrate, a method for fabricating the same and a display device. The array substrate comprises: a substrate, a gate electrode, a gate insulating layer as well as an active layer, and a source/drain metal layer formed on the substrate, the source/drain metal layer is configured for forming a source electrode, a drain electrode and a channel region, wherein a region of the S/D metal layer for forming the channel region is at a lower height than other region of the S/D metal layer for forming the source electrode and the drain electrode.