A level converter and an operation method thereof, a gate driving circuit and a display device. The level converter includes: N input terminals, configured to receive N input signals; N control signal terminals, configured to receive N control signals; N output terminals, configured to output N output signals; and a level converting unit, connected to the N input terminals, the N control signal terminal and the N output terminals and configured to, according to a n-th control signal of the control signal terminals, determine to directly output a n-th input signal as a n-th output signal, or convert the n-th input signal and then output the converted n-th input signal as the n-th output signal; wherein when the n-th input signal is converted, the n-th input signal has shorter rise time and the n-th output signal has longer rise time, and N is a positive integer, 1≤n≤N.