The invention discloses a switch voltage-stabilizing circuit which can regulate switching frequency as well as current peak, has high efficiency and has no audio-frequency noise generated in a state of light load, and method thereof. The switch voltage-stabilizing circuit comprises an energy storage component capable of storing energy; a switch electrically coupled to the energy storage component, wherein the energy storage component can store energy when the switch is on, and the energy stored in the energy storage component is transmitted to a load when the switch is off; a control circuit electrically coupled to the switch, wherein the control circuit compares current flowing through the switch with a current threshold, when the current flowing through the switch is more than the current threshold, the switch is off, and the control circuit determines on and off time of the switch according to the load of the switch voltage-stabilizing circuit, when the load becomes big, the on and off time of the switch is reduced, and when the load becomes small, the on and off time of the switch is increased. The current threshold is constant when the circuit has no light load and becomes low with the load reduced when the circuit has light load.