A TFT substrate for a touch display panel of reduced thickness defines a display area and a surrounding non-display area. The TFT substrate includes a first conductive layer on the substrate and a second conductive layer on the first conductive layer. In the display area, the first conductive layer includes data lines and the second conductive layer includes common electrodes. Each common electrode extends as a strip along a first direction. Each data line extends along a second direction. The first direction intersects the second direction. Each data line crosses the common electrodes. Each data line functions as a touch driving electrode and each common electrode functions as a touch sensing electrode.