A quick charging method, a power adapter, and a mobile terminal are provided. The method includes: transmitting, by the power adapter, clock signal to the mobile terminal via a first data line of the USB interface in a process of that the power adapter is coupled to the mobile terminal, in which the clock signal indicates a communication sequence between the power adapter and the mobile terminal; conducting, by the power adapter, a bidirectional communication with the mobile terminal via a second data line of the USB interface under control of the communication sequence, so as to determine to charge the mobile terminal in the quick charging mode; and adjusting, by the power adapter, a charging current of the power adapter to the charging current corresponding to the quick charging mode to charge the mobile terminal.