Although behavior of hydrogen (H) in oxides does not directly corelate to that in metals, it strongly correlated to H entryH entry in or release from the metals. Stable oxides such as Al2O3, BeOBeO, Er2O3ErO, and Y2O3YO are used as a permeationPermeation barrierPermeation barrier, and some are used as inclusionsInclusion or precipitatesPrecipitate in steels to improve their mechanical properties, which could work as trappingTrapping sitesTrapping site. Hence the knowledge on H behavior in or interaction with oxides are quite important in the investigation of H interactions or behavior in practical steels and alloys. AlthoughH diffusion H diffusionDiffusion and migration in oxides, particularly proton conductorsProton conductor, are quite important, their mechanisms are not understood well. Different from metals, H interacts with oxygenOxygen to make hydroxideHydroxide, which makesH diffusion H diffusionDiffusion in oxides very complex at intermediate to high temperatures. In the oxide precipitatesPrecipitate in metals, H is very likely bound to their surface. Even H2OWater (HO) molecules could be adsorbed on them. Therefore, during theThermal desorption thermal desorptionDesorption of H in meals, such H, OHOH and H2O would be subjected to chemical changes to make H desorption complex.