The embodiments provide a method for reading and writing and a memory device. The method includes: applying a read command to the memory device, the read command pointing to address information; reading data to be read out from a memory cell corresponding to the address information pointed to by the read command; storing the address information pointed to by the read command into a memory bit of a preset memory space if an error occurs in the data to be read out, wherein the preset memory space is provided with a plurality of the memory bits, each of the plurality of memory bits being associated with a spare memory cell; and backing up the address information stored in the preset memory space into a non-volatile memory cell according to a preset rule.