A quick charging method, a power adapter and a mobile terminal are provided. The method is applied to the power adapter, the power adapter is coupled to the mobile terminal through a USB interface, a power line in the USB interface is used by the power adapter to charge the mobile terminal, a data line in the USB interface is used by the power source adapter to conduct a bidirectional communication with the mobile terminal, and the power adapter supports a common charging mode and a quick charging mode, charging current of the quick charging mode is greater than that of the common charging mode. The method includes: conducting a bidirectional communication with the mobile terminal to determine to charge the mobile terminal in the quick charging mode; and adjusting charging current to charging current corresponding to the quick charging mode to charge the mobile terminal.