Abstract: A mobile device for power supply and data storage is proposed, which includes a power supply module, an input/output interface module, a controlling module and a memory module. When the foregoing mobile device is externally connected with a small mobile electric device, power outputted from an output circuit of the power supply module to the electric device can be adjusted by the controlling module, so as to provide a suitable amount of power for the electric device. Moreover, when data storage of the electric device is insufficient for storing further data, the controlling module allows a write in/read out unit of the input/output interface module to write in the data, and then transmits the data to the memory module to be stored therein.