The invention relate to the field of a charging circuit, in particular to a dual-charging circuit compatible with a USB and a DC and a running method of the dual-charging circuit. The circuit comprises a USB power path, a DC power path, a charging circuit, a battery, a power management integrated circuit PMIC, a diode D1, a diode D2, a capacitor C1 and a capacitor C3, wherein the USB power path comprises a field-effect transistor Q1, a field-effect transistor Q2, a capacitor C2, a resistor R1, a resistor R2, a resistor R3, a resistor R4 and a resistor R5. Meanwhile, the invention also providesa running method based on the circuit. The circuit disclosed by the technical scheme is mainly applied to intelligent Tablet and other platforms which do not have functions of multi-path charging; particularly, under the condition that a USB interface of the Tablet is needed to supply power to external equipment for a long time, a machine table can be enabled to be discharged and also charged; and the circuit is built by employing a separate component, an integrated circuit is not used, and the circuit has the characteristics of simplicity and low cost.