A mobile terminal comprises: a download controller configured to download firmware upgrade information data of a power adapter, the firmware upgrade information data configured to upgrade firmware of the power adapter; a first sending controller configured to transmit the firmware upgrade information data to a processor of the power adapter through a data line in a charging port when the mobile terminal is electrically coupled to the power adapter through the charging port to facilitate the processor to upgrade the firmware of the power adapter according to the firmware upgrade information data; characterized in that the mobile terminal further comprises: a judge controller configured to determine whether a power supply device plugged in is the power adapter through a first link, wherein the first link connects a USB port of an application processor of the mobile terminal and the charging port; and a link switching controller configured to switch the mobile terminal from the first link to a second link through a USB switch when determining that the power supply device plugged in is the power adapter, wherein the second link connects a Microcontroller Unit of the mobile terminal and the charging port; the first sending controller being configured to transmit data in accordance with a predetermined format to a predetermined port of the processor of the power adapter through the second link. a download controller configured to download firmware upgrade information data of a power adapter, the firmware upgrade information data configured to upgrade firmware of the power adapter; a first sending controller configured to transmit the firmware upgrade information data to a processor of the power adapter through a data line in a charging port when the mobile terminal is electrically coupled to the power adapter through the charging port to facilitate the processor to upgrade the firmware of the power adapter according to the firmware upgrade information data; characterized in that the mobile terminal further comprises: a judge controller configured to determine whether a power supply device plugged in is the power adapter through a first link, wherein the first link connects a USB port of an application processor of the mobile terminal and the charging port; and a link switching controller configured to switch the mobile terminal from the first link to a second link through a USB switch when determining that the power supply device plugged in is the power adapter, wherein the second link connects a Microcontroller Unit of the mobile terminal and the charging port; a judge controller configured to determine whether a power supply device plugged in is the power adapter through a first link, wherein the first link connects a USB port of an application processor of the mobile terminal and the charging port; and a link switching controller configured to switch the mobile terminal from the first link to a second link through a USB switch when determining that the power supply device plugged in is the power adapter, wherein the second link connects a Microcontroller Unit of the mobile terminal and the charging port; the first sending controller being configured to transmit data in accordance with a predetermined format to a predetermined port of the processor of the power adapter through the second link.