Abstract: The diffusion and permeation behavior of deuterium in Incoloy800H alloy was researched by using gas permeation technology. The permeability experimental curve of deuterium was measured by high temperature experimental system and quadrupole mass spectrometer (QMS) at the temperature range of 450-600 ℃ and 110 kPa. The permeability and diffusion coefficient of deuterium in the plate Incoloy800H alloy were calculated, and the results were fitted with the Arrhenius equation. The experimental results show that the permeation of deuterium in Incoloy800H alloy is the diffusion control step, and the deuterium diffusivity and permeability obey to the Arrhenius relation under the experimental temperature.