Abstract: The hydrogen isotopic deuterium and tritium from gas phase to liquid phase by hydrogen-water exchange were experimentally researched with mixture of hydrophobic catalyst and hydrophillic packing in catalytic bed. The transformation rate and volume transfer coefficient of D and T were determined at various temperature, gas and liquid flow rates．The results show that the transformation rate η(H-T) of T is higher than η(H-D) of D, and the volume transfer coefficient Kya(H-T) of H-T is higher than Kya(H-T) of H-D, the preferable transformation rate and volume transfer coefficient can be obtained by choosing suitable operational temperature. 45 ℃ is the suitable operational temperature in practical technique．