A shift register of a gate driving circuit includes a pull-up unit for pulling up a first output signal and a first gate signal to a high voltage level according to a driving voltage and a high-frequency clock signal, a start-up unit for transmitting a second gate signal, an energy-store unit for providing the driving voltage to the pull-up unit according to the second gate signal, a first discharging unit for pulling down the driving voltage to a first voltage level according to a first control signal, a first leakage-preventing unit for turning off the first discharging unit when the first gate signal reaches the high voltage level, a first pull-down unit for respectively pulling down the first output and first gate signals to the first and a second voltage levels according to the first control signal, and a first control unit for generating the first control signal.