This application discloses a multi-battery power supply, a charging/discharging method, and an electronic device. A power supply circuit includes a first circuit, a second circuit, a first switch, a second switch, a first battery, and a second battery. When the first switch is off, a first controlled terminal of the second switch is electrically connected to a second controlled terminal of the second switch, and when the first circuit is on, the first circuit and the second circuit are configured to supply power to two batteries. When the first switch is on, the first controlled terminal of the second switch is electrically connected to the third controlled terminal of the second switch, and when the first circuit is off, both the batteries supply power to the outside through the second circuit.