The invention discloses a displacement chromatography hydrogen isotope separation device which comprises a rack as well as a cooling part, a separation column, an air supply part, an air collection part, a lifting part and a driving part. By adopting the displacement chromatography hydrogen isotope separation device disclosed by the invention, different adsorption functions that hydrogen and hydrogen isotope are replaced and separated by using a separation material can be achieved, the lifting part is driven by the driving part to precisely control the lifting position of the separation column, and then the separation column can be descended or lifted off the cooling part, so that adsorption or desorption of hydrogen isotope by the separation material under different temperature conditions can be achieved, a high retention rate of deuterium-tritium isotope in the separation material can be ensured, and a deuterium-tritium isotope gas obtained through final separation and selection is relatively high in purity; compared with the prior art, the device needs no parts for introducing deuterium or separating deuterium, meanwhile deuterium and tritium do not need to be replaced by introducing hydrogen after the separation material is in saturation adsorption of hydrogen, and in addition, the device is simple in structure, low in energy consumption rate, simple in process and low in cost.