A thin film transistor array substrate includes a gate line formed on a substrate, a data line formed on the substrate intersecting with the gate line to define a pixel region, a thin film transistor formed at the intersection of the gate line and the data line, the thin film transistor including gate electrode formed on the substrate, a gate insulating layer formed on the gate electrode and the substrate, a semiconductor layer formed on the gate insulating layer,an ohmic contact layer on the semiconductor layer, and a source electrode and a drain electrode on the ohmic contact layer, and a transparent electrode material within the pixel region and connected to the drain electrode of the thin film transistor, wherein the gate insulating layer includes a gate insulating pattern underlying the data line and the transparent electrode material, and covering the gate line.