by the way sir, i am trying to save the data in that memory but if i remove the power from MCU then data from memory of DS1307 if lost.. BUT its still in the DS1307 NVRAM 56byte memory.
Like Eric says, the NVRAM in the DS1307 might be battery backed RAM rather than EEPROM?, so you need a backup battery to maintain it, and keep the clock running when there's no power. Again, the datasheet will explain it all.