A method for fabricating a TFT array substrate, comprising: forming an initial conductive layer on a base substrate, wherein the initial conductive layer comprises a pre-plating electrode layer and a plating electrode layer; forming a first oxidation preventing layer in a first preset region on the initial conductive layer, wherein the first preset region corresponds to an electrode connecting part; forming a second oxidation preventing layer in a second preset region on the initial conductive layer, wherein the second preset region corresponds to a portion of the initial conductive layer that is to be removed; performing an oxidization process to partially oxidize the initial conductive layer to form an oxidized insulating sub-layer and a non-oxidized conductive sub-layer, wherein: the oxidization process comprises performing an electrolytic oxidation treatment, the oxidized insulating sub-layer comprises an oxidized portion of the plating electrode layer, and the non-oxidized conductive sub-layer comprises a non-oxidized portion of the plating electrode layer and the pre-plating electrode layer; removing the first oxidation preventing layer and the second oxidation preventing layer, wherein the electrode connecting part is a non-oxidized portion of the initial conductive layer that is covered by the first oxidation preventing layer; removing the pre-plating electrode layer and the plating electrode layer in the second preset region; and forming an active layer, a source electrode and a drain electrode over the oxidized insulating sub-layer in a gate electrode region. forming an initial conductive layer on a base substrate, wherein the initial conductive layer comprises a pre-plating electrode layer and a plating electrode layer; forming a first oxidation preventing layer in a first preset region on the initial conductive layer, wherein the first preset region corresponds to an electrode connecting part; forming a second oxidation preventing layer in a second preset region on the initial conductive layer, wherein the second preset region corresponds to a portion of the initial conductive layer that is to be removed; performing an oxidization process to partially oxidize the initial conductive layer to form an oxidized insulating sub-layer and a non-oxidized conductive sub-layer, wherein: the oxidization process comprises performing an electrolytic oxidation treatment, the oxidized insulating sub-layer comprises an oxidized portion of the plating electrode layer, and the non-oxidized conductive sub-layer comprises a non-oxidized portion of the plating electrode layer and the pre-plating electrode layer; the oxidization process comprises performing an electrolytic oxidation treatment, the oxidized insulating sub-layer comprises an oxidized portion of the plating electrode layer, and the non-oxidized conductive sub-layer comprises a non-oxidized portion of the plating electrode layer and the pre-plating electrode layer; removing the first oxidation preventing layer and the second oxidation preventing layer, wherein the electrode connecting part is a non-oxidized portion of the initial conductive layer that is covered by the first oxidation preventing layer; removing the pre-plating electrode layer and the plating electrode layer in the second preset region; and forming an active layer, a source electrode and a drain electrode over the oxidized insulating sub-layer in a gate electrode region.