A scan driving circuit is provided for driving scan line in cascade, including a pull-down controlling module, a pull-down module, a reset-controlling module, a resetting module, a downward-transferring module, a first bootstrap capacitor, a constant low voltage level source, and a constant high voltage level source. By disposing the resetting module, the scan driving circuit of the present invention raises the reliability of the scan driving circuit and simplifies the entire structure of the scan driving circuit.