A control method of a single live line charging circuit, a control circuit of a single live line charging circuit, and a single live line charging circuit are provided. The single live line charging circuit includes a first switch, a first conduction element, a first inductor, a second switch, a second conduction element, a third switch, a first input end and a second input end; the first input end is connected to a first end of the first switch through the second conduction element; the first switch, the first conduction element and the first inductor constitute a buck circuit; the first input end is connected to a reference ground through the second switch, the second input end is connected to the reference ground through the third switch, and an alternating current input is connected to the first input end through a load circuit.