The invention discloses a battery charging and discharging circuit which comprises a power level circuit, a first switch and a second switch. A first input end of the power level circuit is connectedwith a high potential end of input voltage, a second input end of the power level circuit is connected with a low potential end of the input voltage, a first output end of the power level circuit is connected with one end of the first switch, the other end of the first switch is connected with a positive electrode of a battery pack, a negative electrode of the battery pack is connected with a second output end of the power level circuit, a load is connected to an output end of the power level circuit, one end of the second switch is connected with the first switch and a common terminal of thebattery pack, and the other end of the second switch is connected with the first input end of the power level circuit. When a battery is charged and discharged, the voltage of two ends of the load iskept.