A thin film transistor (TFT) array substrate having a display region, a pad pending region, and a wiring region connected to the display region and the pad pending region is disclosed and includes a substrate function layer and a plurality of metal layers disposed over the substrate function layer, which includes a substrate layer and all of a buffer layer, an active layer, and a first insulation layer disposed over the substrate layer, wherein the metal layers include a first metal layer, a second metal layer, and a third metal layer separately disposed within the display region and made of a same metal material including aluminum or aluminum alloy. Another aspect of the present disclosure provides a TFT array substrate, a plurality of material layers disposed therein are adopted of a material with low resistance low electrical resistance and being excellent in bending resistance.