Abstract: The tritium decays into ³He naturally, and the accumulation of ³He will cause obvious changes in physical and chemical property of the Tritium storage materials. In this paper, the titanium tritide was selected to be the object of the research, and the evolution law of its crystal structure in the initial stage of storage was studied by XRD. The distribution of ³He in titanium tritide and its aging behavior in the initial stage of storage were also studied. The results indicate that the characteristic peak broadening of titanium tritide is caused by the accumulation of ³He which tritium decays into. The crystal structure of titanium tritide keeps constant as fcc structure.