A thin film transistor (TFT) substrate includes: a substrate; a plurality of scan lines, disposed on the substrate; a plurality of data lines, disposed across the scan lines; a scan line insulting layer disposed between the scan lines and the data lines; a plurality of thin film transistors, each of thin film transistors disposed on an intersection of each scan line and each data line; a data line insulting layer, disposed on a top surface of the scan line insulting layer and used to cover the data lines; and a common electrode, disposed on the data line insulting layer, and comprising a plurality of positioning through holes, wherein the positioning through holes expose the data line insulting layer, and are located right above the data lines.