Abstract: Disclosure is related to a method for transmitting data, and the method is applicable to a mobile storage apparatus. The mobile storage apparatus provides multiple electronic devices to wirelessly access the files stored in the apparatus. The apparatus determines a scheme to segment the files to be sent according to the files' types, sizes and the order of the connected devices. The files are segmented into multiple sections before the transmission. A power management unit may turn off a communication unit within the apparatus when the transmission procedure enters an idle state. When the jobs in the electronic devices have been completed, the communication unit is again turned on for transmitting next segment until the files are completely transmitted. The invention achieves efficient transmission in a power-saving mode.