An array substrate, a display device and a method of producing the array substrate are provided, and the array substrate includes a substrate and a thin film field effect transistor and a data line formed on the substrate, and the thin film field effect transistor includes a gate electrode, an active layer, a source electrode and a drain electrode, a gate insulating layer is formed between the gate electrode and the active layer, and the array substrate includes: a protection layer formed between the gate insulating layer and the data line and being in direct contact with the data line; and the protection layer is provided on the same layer with and has the same material with the active layer.