A quick charging method applied in a power adapter, the power adapter being coupled to a mobile terminal via a USB interface, a power line of the USB interface being used for the power adapter to charge a battery of the mobile terminal, data lines of the USB interface being used for communication between the power adapter and the mobile terminal, the power adapter supporting a normal charging mode and a quick charging mode, a charging speed of the quick charging mode being greater than that of the normal charging mode, the method comprising: activating, by the power adapter, a quick charging communication process when the power adapter receives indication information for indicating that the mobile terminal has recognized that the power adapter is not a computer from the mobile terminal, and transmitting, by the power adapter, a first instruction to the mobile terminal, the first instruction being configured to query whether the mobile terminal agrees to charge the battery in the quick charging mode; receiving, by the power adapter, a reply instruction of the first instruction from the mobile terminal, the reply instruction of the first instruction being configured to indicate that the mobile terminal agrees to charge the battery in the quick charging mode; conducting, by the power adapter, a handshake communication with the mobile terminal via a second instruction to determine a charging voltage of the quick charging mode; conducting, by the power adapter, a handshake communication with the mobile terminal via a third instruction to determine a charging current of the quick charging mode; and adjusting, by the power adapter, an output voltage and an output current of the power adapter to be the charging voltage and the charging current of the quick charging mode to enter a constant current phase; and conducting, by the power adapter, a handshake communication with the mobile terminal via a fourth instruction during the constant current phase to adjust the output current of the power adapter, so as to charge the mobile terminal in a multi-stage constant current mode, wherein, in the multi-stage constant current mode, the output current of the power adapter is changed periodically. activating, by the power adapter, a quick charging communication process when the power adapter receives indication information for indicating that the mobile terminal has recognized that the power adapter is not a computer from the mobile terminal, and transmitting, by the power adapter, a first instruction to the mobile terminal, the first instruction being configured to query whether the mobile terminal agrees to charge the battery in the quick charging mode; receiving, by the power adapter, a reply instruction of the first instruction from the mobile terminal, the reply instruction of the first instruction being configured to indicate that the mobile terminal agrees to charge the battery in the quick charging mode; conducting, by the power adapter, a handshake communication with the mobile terminal via a second instruction to determine a charging voltage of the quick charging mode; conducting, by the power adapter, a handshake communication with the mobile terminal via a third instruction to determine a charging current of the quick charging mode; and adjusting, by the power adapter, an output voltage and an output current of the power adapter to be the charging voltage and the charging current of the quick charging mode to enter a constant current phase; and conducting, by the power adapter, a handshake communication with the mobile terminal via a fourth instruction during the constant current phase to adjust the output current of the power adapter, so as to charge the mobile terminal in a multi-stage constant current mode, wherein, in the multi-stage constant current mode, the output current of the power adapter is changed periodically.