A method for reading and writing, performed by a dynamic random access memory, DRAM, comprising: receiving a read command, the read command pointing to address information; looking up, from a lookup table, a mark corresponding to the address information pointed to by the read command by taking the address information pointed to by the read command as an index, wherein the lookup table comprises a column of address information and a column of mark information, each mark information of the column of mark information having a corresponding address information stored in the address information column; determining whether the mark information corresponding in the look up table to the address information pointed to by the read command is valid; performing, if the mark information corresponding in the look up table to the address information pointed to by the read command is valid, a read operation on the memory cells corresponding to the address information pointed to by the read command to read data to be read out; obtaining a determination result by determining, if the mark information corresponding in the look up table to the address information pointed to by the read command is invalid, whether the address information pointed to by the read command has been changed to another address information and a write command has been executed on the another address information after the mark information corresponding in the look up table to the address information pointed to by the read command is set as invalid; pointing the read command to the another address information pointed to by the write command to perform the read operation on memory cells corresponding to the another address information if the determination result is yes; stopping the read operation if the determination result is no; setting the mark of the address information pointed to by the read command as invalid if an error occurs in the data to be read out; having the mark of the address information pointed to by the read command be unchanged if no error occurs in the data to be read out; outputting the data to be read out; and backing up the address information pointed to by the read command and the mark into non-volatile memory cells according to a preset rule, wherein the preset rule is a preset time period, the back up being performed every period, or the preset rule is a trigger operation received by the DRAM, the back up being performed according to the trigger operation. receiving a read command, the read command pointing to address information; looking up, from a lookup table, a mark corresponding to the address information pointed to by the read command by taking the address information pointed to by the read command as an index, wherein the lookup table comprises a column of address information and a column of mark information, each mark information of the column of mark information having a corresponding address information stored in the address information column; determining whether the mark information corresponding in the look up table to the address information pointed to by the read command is valid; performing, if the mark information corresponding in the look up table to the address information pointed to by the read command is valid, a read operation on the memory cells corresponding to the address information pointed to by the read command to read data to be read out; obtaining a determination result by determining, if the mark information corresponding in the look up table to the address information pointed to by the read command is invalid, whether the address information pointed to by the read command has been changed to another address information and a write command has been executed on the another address information after the mark information corresponding in the look up table to the address information pointed to by the read command is set as invalid; pointing the read command to the another address information pointed to by the write command to perform the read operation on memory cells corresponding to the another address information if the determination result is yes; stopping the read operation if the determination result is no; setting the mark of the address information pointed to by the read command as invalid if an error occurs in the data to be read out; having the mark of the address information pointed to by the read command be unchanged if no error occurs in the data to be read out; outputting the data to be read out; and backing up the address information pointed to by the read command and the mark into non-volatile memory cells according to a preset rule, wherein the preset rule is a preset time period, the back up being performed every period, or the preset rule is a trigger operation received by the DRAM, the back up being performed according to the trigger operation.