A pixel array substrate includes a substrate, a plurality of pixel structures, a plurality of signal lines, a plurality of first traces, a plurality of second traces, a plurality of first conductive structures, and a plurality of second conductive structures. The pixel structures are arranged in array in a display region of the substrate. The signal lines are disposed in the display region and are formed in a first conducting wire layer and are electrically connected to the pixel structures. The first traces and the second traces are disposed in a periphery circuit region of the substrate and are respectively formed in a second conducting wire layer and the first conducting wire layer. A part of the signal lines are electrically connected to the first traces by the first conductive structures. Another of the signal lines are electrically connected to the second traces by the second conductive structures.