A DC-to-DC controller, a DC-to-DC power converter and a control method thereof are provided. The controller is coupled to an upper-bridge switch and a lower-bridge switch and includes a time generation unit providing a time signal, a voltage identification (VID) change determining circuit and a time control circuit. The VID change determining circuit provides a determination signal in response to a VID signal. The time control circuit provides a control signal according to the time signal and the determination signal. When the VID signal changes from high to low, the time control circuit turns off the upper-bridge switch for a first preset time according to the determination signal and the time signal, and during the first preset time, the time control circuit controls the lower-bridge switch to be turned on for a second preset time multiple times, and to be turned off for a third preset time multiple times.