The present invention provides a method for accessing a flash memory module, wherein the flash memory module comprises at least one flash memory chip, each flash memory chip comprises a plurality of blocks, each block comprises a plurality of pages, and the method comprises: sending a read command to the flash memory module to ask for data on at least one memory unit; and analyzing state information of a plurality of memory cells of the memory unit based on information from the flash memory module to determine a decoding method adopted by a decoder.