A power adapter (200) and a terminal (100). The terminal (100) comprises a battery (110) and a charging interface (120), the terminal (100) introducing a charging current from the power adapter (200) via the charging interface (120) so as to charge the battery (110); and the terminal (100) further comprises: a communication unit (130), the communication unit (130) performing bi-directional communication with the power adapter (200) via the charging interface (120) so as to determine a charging mode of the terminal (100). The power adapter (200) negotiates with the terminal (100) about the charging mode via the communication unit (130), and the output voltage/output current of the power adapter (200) is controlled according to the charging mode determined by the communication unit (130), so that the heating and even burning phenomena of a mobile phone caused by the aimless increase of the voltage or current of the power adapter (200) can be effectively avoided.