Abstract: A fabricating method of a field emission device array substrate is provided, which includes the following steps. First, a substrate is provided. Then, a cathode conductive layer is formed on the substrate. Moreover, an anodized layer with a plurality of holes is formed on the cathode conductive layer. Thereafter, a plurality of electron emitters is formed within the holes respectively. Additionally, an insulation layer is formed to cover the electron emitters and the anodized layer. Then, a gate material layer is formed on the insulation layer. Thereafter, the gate material layer is patterned to form a gate layer. The gate layer and the insulation layer have an opening to expose the electron emitters.