The embodiments of the disclosure discloses a method of driving a dynamic backlight and a display device. In this method, a vertical synchronization signal corresponding to an input image signal is received; a first level signal and a second level signal are outputted alternately in response to a change edge of the vertical synchronization signal, where the total duration of the first level signal and the second level signal is 1/m of the duration between the change edge and a first change edge before the change edge, wherein the change edge and the first change edge before the change edge are change edges of a same changing direction; m is a positive integer; and the drive chip receives the first level signal and the second level signal and generates a PWM signal according to the first level signal and the second level signal.