The method for managing flash memory data includes the following steps. When data are first transmitted from a host and the address for the data indicates a temporary address, then temporary data are retrieved from the temporary address to an external buffer. A writing command is then executed and the temporary data having a destination address are written to a flash buffer. When the buffer of the flash memory is not full, the buffer data are written into a temporary block. The method of writing the buffer data into the temporary block includes using a address changing command, or executing a writing command to rewrite the external buffer data to the flash buffer so that the data are written into the temporary block.