A memory device includes a non-volatile memory chip, a connector and a memory controller. The non-volatile memory chip includes an access partition and a hidden partition. The memory controller is used to set first logical blocks mapping to mapping physical blocks in the access partition. The memory controller is used to maintain a first mapping table recording the first logical blocks and the mapping physical blocks. During backup, the memory controller is used to duplicate data in the mapping physical blocks to the hidden partition according to the first mapping table to form backup physical blocks, and establish a second mapping table setting second logical blocks to map to the backup physical blocks. During recovery, the memory controller is used to map the second logical blocks to the backup physical blocks according to the second mapping table for the host system to recover an environment set at the backup operation.