Abstract: The hydrogen absorbed on solid surface can exchange with its isotopes in gas phase until equilibrium achieved. Such characteristic exists in metal hydride-hydrogen system,too. Because of the hydrogen isotope effects in metal hydride-hydrogen system,abundances of hydrogen isotopes are different between solid and gas phase under exchange equilibrium. With this character, the displacements between hydrogen isotopes can be conducted in metal hydride packing column, further, and some important applications in engineering can be achived.