The invention provides a method for handling data updating of a flash memory. In one embodiment, the flash memory comprises a mother block comprising a plurality of updated pages to be updated. First, a spare block, recording no data, is popped as a file allocation table (FAT) block corresponding to the mother block. Data for updating the updated pages of the mother block is then written to a plurality of replacing pages of the FAT block. Finally, a plurality of mapping relationships between the replacing pages and the updated pages are recorded in a page mapping table stored in the FAT block.