The present disclosure relates to a metal oxide thin-film transistor and a manufacturing method therefor, a display panel and a display apparatus, which belong to the technical field of displays. The metal oxide thin-film transistor comprises a gate electrode, a gate insulating layer, a metal oxide semiconductor layer, a source electrode and a drain electrode, and a passivation layer, which are sequentially arranged on a base substrate, wherein the source electrode and the drain electrode each have a stacked structure, the stacked structure of the source electrode or the drain electrode at least comprises a main body metal layer and an electrode protection layer, and the electrode protection layer contains metal or metal alloy; the electrode protection layer is at least arranged between the metal oxide semiconductor layer and the main body metal layer; a metal oxide layer is provided between the electrode protection layer and the main body metal layer, and a metal element of the metal oxide layer comprises at least one of a metal element of the main body metal layer and a metal element of the electrode protection layer; the thickness of the metal oxide layer does not exceed 2% of the thickness of either one of the source electrode and the drain electrode; and the thickness of the metal oxide layer does not exceed 10% of the thickness of the electrode protection layer.