A pixel array having a plurality of pixel structures is provided. At least one of the pixel structures includes a scan line, a data line, an active device, a pixel electrode, a capacitor electrode line, a readout line and a sensing device. The scan line and the data line are disposed on a substrate. The active device is electrically connected to the scan line and the data line. The pixel electrode is electrically connected to the active device. The capacitor electrode line electrically couples with the pixel electrode. The readout line is disposed parallel to the data line. The sensing device is electrically connected to the scan line and the readout line, and the sensing device is connected to an adjacent capacitor electrode line.