A display driving circuit with photo detecting input includes pixel regions, pixel electrodes, gate lines, data lines, at least one photo detecting unit and at least one readout line. The gate lines cross the data lines. The data lines include a first data line and a second data line disposed adjacently to each other. There is no data line disposed between the first data line and the second data line. The photo detecting unit is electrically connected to one of the gate lines. The readout line is electrically connected to the photo detecting unit and disposed between the first data line and the second data line. A first spacing between first data line and the readout line is wider than or equal to a second spacing between the second data line and the readout line, and the first spacing is smaller than or equal to triple the second spacing.