The present invention provides an apparatus for security of accessing data, comprising a storage device including an address transform detector, a first lock bit register and a data comparator, the address transform detector providing a predetermined correction signal, data outputted from the storage device could be correctly identified when a memory address signal matches the predetermined correction signal and a latch signal is provided to the first lock bit register; and a micro-control unit for receiving data outputted from the storage device, the outputted data being stored in a second lock bit register and encoded by a serial encoding unit, a locking signal being feedback to the storage device; wherein a data encoded signal outputted from the first lock bit register and the locking signal are provided to a data comparator for comparison and determining whether output correct data to an encoding control unit according to the comparison.