This disclosure relates to a DC-charging power source adaptor including a charging interface, an AC to DC converting unit, and a controlling unit; and the DC-charging power source adaptor is timed to communicate with a mobile terminal which is a charging object, to acquire a change in voltage of a battery in the mobile terminal and further adjust dynamically a volt value of charging voltage output by the DC-charging power source adaptor according to the change in voltage of the battery, and DC-charges the battery in the mobile terminal using the charging voltage.