This disclosure provides a mobile terminal, a DC-charging power source adaptor, and a charging method, where firstly the DC-charging power source adaptor is configured to communicate with the mobile terminal in a UART communication mode, and then a strategy to identity the type of charging is designed in the mobile terminal dependent upon configuration of communication pins of a different charging device, so that the mobile terminal identifies automatically the type of the external device. Also a specialized rapid charging mode is designed for the DC-charging power source adaptor, the battery of the mobile terminal being charged is DC-charged at large current by charging voltage output by the DC-charging power source adaptor, and the volt value of the charging voltage is adjusted dynamically according to the varying voltage of the battery.