Abstract: A series of 2,2′-(arylimino)-diethyl-sodium thiosulfate was synthesized and tested in mice for radiation-protective activity. Preiimary data showed that the position of the subsitution group in the benzene ring played significant role for the radio-protective action, the protection of meta-subsitution is better than that of para-subsitution. Among these, compounds 5 and 8 exhibited marked protection against ionizing radiation in mice.