The present application discloses a fabrication method for forming an array substrate, including: forming, in a fanout region, a first signal-load line connected to a first group of data lead wires, and a second signal-load line connected to a second group of data lead wires; and forming, in the fanout region, at least one unidirectional device at a connection point of the first signal-load line and a data lead wire, at least one unidirectional device at a connection point of the second signal-load line and a data lead wire. The first signal-load line and the second signal-load line are each configured to transmit an external testing signal along a single direction to the data lead wires through the unidirectional devices.