A block control device for a semiconductor memory and a method for controlling the same are disclosed, which relate to a technology for controlling a block operation state of a Low Power Double-Data-Rate 2 (LPDDR2) non-volatile memory device. A block control device for use in a semiconductor memory includes a block address comparator configured to compare a first block address with a last block address, and output a same pulse or unequal pulse according to the comparison result, a block address driver configured to output a lock state control signal for driving a block address in response to the same pulse, a block address counter configured to count block addresses from the first block address to the last block address in response to the unequal pulse, and generate a block data activation pulse, and a block address register configured to store a lock state of a corresponding block in response to the lock state control signal and the block data activation pulse.