A method for accessing a flash memory module includes: selecting a block in the flash memory module; selecting a specific encoding/decoding setting from a plurality of sets of encoding/decoding settings at least according to an erase count of the block, wherein the plurality of sets of encoding/decoding settings include different error correction code (ECC) lengths, respectively; utilizing the specific encoding/decoding setting to encode a data to generate an encoded data; and writing the encoded data into the block.