The invention provides a method for accessing a flash memory module, wherein the method includes the steps of: classifying multiple read retry tables into at least a first group and a second group to establish a classifying and sorting table, wherein each of the multiple read retry tables records at least one reading voltage, and any two read retry tables do not have exactly the same reading voltage; selecting a first read retry table from the first group to read a page of a block of the flash memory module to generate first read data; and when a decoder fails to decode the first read data, selecting a second read retry table from the first group to read the page of the block of the flash memory module to generate second read data for the decoder to decode.