An array substrate and a display device are presented. The array substrate includes: a base substrate and a plurality of thin film transistor units located on the base substrate, wherein, the thin film transistor unit includes: a first gate electrode located on the base substrate, a gate insulating layer located on the first gate electrode, a drain electrode disposed in the same layer as the first gate electrode, an active layer located on the drain electrode, a source electrode located on the active layer, a first transparent conductive layer is provided between the base substrate and the first gate electrode and the drain electrode that are disposed in the same layer, and the gate insulating layer is also disposed between the first gate electrode plus the first transparent conductive layer beneath it and the drain electrode plus the first transparent conductive layer beneath it.