A flash memory control method, storing a logical-to-physical address mapping relationship between a host and a flash memory and a root table in the flash memory and providing a non-volatile storage area storing a root table pointer. A mapping relationship pointer is set forth in the root table to show where the logical-to-physical address mapping relationship is stored in the flash memory. The root table pointer points to the root table stored in the flash memory. In response to a power restoration request issued from the host, the flash memory is accessed based on the root table pointer and thereby the root table is read and the logical-to-physical address mapping relationship is retrieved from the flash memory based on the mapping relationship pointer set forth in the root table.