A method for handling data updating of a flash memory is disclosed, in which the flash memory comprises a mother block with a plurality of pages to be updated, and each page comprises a plurality of sectors. In such method, a first data for updating a target page in the mother block is obtained, and then whether the first data comprises data for updating an ending sector in the target page is determined. The first data is written into a replacing page in a first FAT block when the first data does not comprise data for updating the ending sector in the target page. The first data is written into a corresponding page in a second FAT block when the first data comprises the data for updating the ending sector, in which the corresponding page in the second FAT block and the target page in the mother block have the same page indexes.