A method for fabricating a metal oxide thin film transistor comprises selecting a substrate and fabricating a gate electrode thereon; growing a layer of dielectric or high permittivity dielectric on the substrate to serve as a gate dielectric layer; growing a first metal layer on the gate dielectric layer and a second metal layer on the first metal layer; fabricating a channel region at a middle position of the first metal layer and a passivation region at a middle position of the second metal layer; anodizing the metals of the passivation region and the channel region at atmospheric pressure and room temperature; fabricating a source and a drain; forming an active region comprising the source, the drain, and the channel region; depositing a silicon nitride layer on the active region; fabricating two electrode contact holes; depositing a metal aluminum film; and fabricating two metal contact electrodes by photolithography and etching.