A pixel array substrate, including a substrate, multiple conductors, a pixel driving circuit, a first pad, and a second pad, is provided. The substrate has a first surface, a second surface, and multiple through holes. The through holes extend from the first surface to the second surface. The conductors are respectively disposed in the through holes. The pixel driving circuit is disposed on the first surface of the substrate. The first pad and the second pad are disposed on the second surface of the substrate. The conductors include a first conductor, a second conductor, and a first dummy conductor. The first conductor is electrically connected to the pixel driving circuit and the first pad. The second conductor is electrically connected to the pixel driving circuit and the second pad. The first dummy conductor is overlapped with and electrically isolated from the pixel driving circuit.