Disclosed are a gate driving unit and a driving method thereof, a gate daring circuit and a display device. The gate driving unit comprises a shift register (SR) and a forward and reverse scanning controller (20), wherein the shift register (SR) comprises a forward input sub-circuit (21) and a reverse input sub-circuit (22). The forward and reverse scanning controller (20) is used for transmitting a first clock signal provided by a first clock signal terminal (CLK1) to the forward input sub-circuit (21) and the reverse input sub-circuit (22) for forward scanning, and transmitting a second clock signal provided by a second clock signal terminal (CLK2) to the forward input sub-circuit (21) and the reverse input sub-circuit (22) for reverse scanning. The forward input sub-circuit (21) is used for transmitting a signal provided by the forward and reverse scanning controller (20) to a pull-up node (PU) under the control of effective signals provided by a forward scanning input terminal (INPUT1); the reverse input sub-circuit (22) is used for transmitting the signal provided by the forward and reverse scanning controller (20) to a pull-up node (PU) under the control of effective signals provided by a reverse scanning input terminal (INPUT2).