The application discloses a power source adaptor for charging directly and a mobile terminal, where the power source adaptor for charging directly is timed to communicate with a mobile terminal which is a charging object, in the UART communication mode to obtain a change in voltage of a battery in the mobile terminal, adjusts dynamically a volt value of charging voltage output by the power source adaptor for charging directly according to the varying voltage of the battery, and charges directly the battery in the mobile terminal using the charging voltage.