Embodiments of the invention provide an oxide TFT and a manufacturing method thereof. The oxide thin film transistor comprises: a substrate; a gate electrode formed on the substrate; a gate insulation layer covering the gate electrode; an oxide active layer formed on the gate insulation layer and comprising a source region, a drain region, and a channel between the source region and the drain region; an etching barrier layer entirely covering the active layer and the gate insulation layer; and a source electrode and a drain electrode formed on the etching barrier layer and respectively provided on both sides of the channel. The etching barrier layer is a metal layer. The oxide thin film transistor further comprises a channel protective layer, which is a non-conductive oxidation layer converted from the metal layer by performing an oxidation treatment on the metal layer.