A low power multimedia playing system is provided. The system includes a portable computer and a portable media player. The portable computer includes an activation switch, an interface, a storage unit, a microcontroller, and a bus controller. The activation switch is for a function of playing audio files. The storage unit is for storing the audio files. The interface configured is for communicating with the portable media player. The microcontroller is operated when the portable computer is not powered, and is programmed for controlling the media player connected thereto to play the audio files stored in storage unit. The bus controller configured is for controlling a battery to supply power to the storage unit and the microcontroller, in response to an operation on the activation switch.