[en] The diffusion parameters of key radionuclides in the hosting rock of a geologic repository are important data for the pre-safety assessment in the stage of site selection and safety assessment for the repository. The influence of temperature on the migration of "1"2"5I in the granite taken from Beishan is investigated by through-diffusion method. The results indicate that the effective diffusion coefficient of iodine increases as the temperature increasing. This may indicate that molecular diffusion is one of the dominant processes of migration and diffusion of iodine in Beishan granite. (authors)