A method, a mobile terminal and a power adapter for quick charging includes: sending, by a mobile terminal, a first instruction indicating that the mobile terminal is operable under the quick charging mode to the power adapter through the at least one data line in the USB interface, the first instruction being configured for instructing the power adapter to adjust an output of the power adapter based on the received first instruction; and receiving, by the mobile terminal, a charging current delivered by the at least one power line and corresponding to the quick charging mode from the power adapter, so as to charge a battery in the mobile terminal.