A method for manufacturing a TFT (Thin-Film Transistor) substrate is proposed. The method includes utilizing a first photomask process to form a buffer layer, a data line, a source electrode, a first scan line, a second scan line, and a gate electrode on a substrate; utilizing a second photomask process to form a first insulation layer, a second insulation layer, a first semiconductor layer, and a second semiconductor layer on the substrate; and utilizing a third photomask process to form a first conductor layer, an electrical connection portion, and a drain electrode on the substrate.