A method of fabricating a thin film transistor array substrate and a thin film transistor array substrate using the same for preventing a deterioration of a picture quality are disclosed. In the method of the thin film transistor array substrate, a transparent conductive material and a metal material are sequentially disposed on a substrate. A first mask process patterns the transparent conductive material and the metal material.
The method forms the active layer of island-shape and the ohmic contact layer at an area which is overlapped with the gate electrode using the second mask process, and forms the source electrode and the drain electrode using the third mask process different from the second mask process. Accordingly, the gate electrode shields a light irradiated from the back light not to be thereby irradiated the light into the active layer of the TFT array substrate of the present invention. Thus, the TFT does not form a channel irregardless of a drive of the TFT array substrate, so that the TFT array substrate can remove a leakage of the pixel voltage signal charged into the pixel electrode. As a result, the TFT array substrate of the present invention can prevent a deterioration of a picture quality of the liquid crystal display device.