Abstract: The researches on the diffusion of key nuclide Se in Beishan granite, which is the pre-selected surrounding rock of China’s high-level radioactive waste geological repository, were summarized, including research methods, relevant data obtained and work to be carried out. Moreover, the influence of temperature on the diffusion of ⁷⁵Se(Ⅳ) in Beishan granite and the possible influence mechanism were analyzed emphatically, in order to provide useful references for domestic peers.