A management method for a non-volatile memory comprises the steps of providing the non-volatile memory with at least one block having a plurality of pages to store user data and parity data; dividing at least one of the pages into a plurality of partitions each including the user data and parity data; determining codeword length of each of the partitions, the codeword length comprising message length with sufficient storage to store the user data and parity length storing the parity data; and storing extra parity data in the partition with the codeword length. When storing extra parity data in the codeword length, the parity length is increased and the message length is decreased.