A charging and discharging circuit is provided, which includes a charging and discharging control circuit, a first connection port, a first switch circuit, a second switch circuit, a second connection port, a third switch circuit, a fourth switch circuit, and an identification logic circuit. The identification logic circuit determines a mode of the first connection port according to a first channel configuration signal of the first connection port, the charging and discharging control circuit switches the first switch circuit and the second switch circuit according to the mode of the first connection port, and the charging and discharging control circuit determines a mode of the second connection port according to a second channel configuration signal of the second connection port, so as to switch the third switch circuit and the fourth switch circuit.