At subcellular level, the chromosome aberration of human peripheral lymphocytes had been popularly accepted as a useful radiation biodosimeter. But at the molecular level, very good biomarkers which could be used clinically in the estimation of radiation damage were still lacking. In the recent years the gene mutation of blood cells deserved much attention. The radiation induced gene mutation occurred in the genome of hematopoitic stem cells in the bone marrow,but could be estimated in the peripheral blood.Such kind of somatic gene mutation has several merits, such as very stable, high radio-sensitivity, good dose-response relationship, and easy to obtain the assay samples clinically. In this paper, the recent advances in the study of radiation induced mutations of hprt gene, T-cell receptor gene, and human leucocyte antigen-A gene of lymphocytes, and glycophorin A gene of red cell precursors were reviewed,and their biological characteristics, current assay methods,and clinical application were discussed.