A TFT array substrate and a process for manufacturing the same are provided. A plurality of TFTs in array are formed on a substrate. A gate insulating layer and a protection layer are sequentially formed to cover a pixel region of the substrate. A plurality of openings each of which has an undercut profile are formed in the gate insulating layer and the protection layer. Then, a transparent conductive layer is formed over the substrate. One of the two parts separated is located in a bottom of the opening and the other is on the protection layer, such that two parts of the transparent conductive layer disconnect and no junction there between occurs. The part of the transparent conductive layer in the bottom of the opening is referred to as a transparent pixel electrode. The part of the transparent conductive layer on the protection layer is connected to a common metal line to form a transparent common electrode. The transparent pixel electrode disconnects to but overlaps the protection layer