A data storage device having self-destruction function is disclosed. The data storage device is inserted into a host and includes a controller, a plurality of flash memories, a trigger, and a backup power module. When the data storage device is pulled out of the host, the trigger is triggered and transmits a physical-destruction activating signal to the backup power module, and the backup power module outputs a high voltage to the flash memories according to the physical-destruction activating signal so that the flash memories can be destroyed by the high voltage.