Background: People are exposed to more radiation than before with the application of radiation technology. Radiation is known to induce damage to cell structure, DNA, chromosomes and nucleus. In this study, we showed that CGJ extract can inhibit radiation-induced chromosomal damage in vivo and NLRP7 inflammasome activation in vitro, suggesting that the compound from CGJ can Be considered as a therapeutic materials to reduce adverse effect inflammation and chromosome aberration during radio-therapy. Materials and methods: In this study the inhibitory effects of Cheonggukjang (CGJ) extract on the radiation-induced micronucleus formation in vivo and the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome activation in vitro. Results: We observed the prolonged presence of radiation-induced inflammation and its onsecutive damage in hematopoietic tissues after irradiation by examining micronucleus formation in polychromatic erythrocytes. Mouse bone marrow-derived macrophages were used to investigate NLRP3 inflammasome activation. The micronucleus analysis with mouse peripheral polychromatic erythrocytes using acridine orange staining showed a significantly (p<0.05) reduced frequency of micronucleated bone marrow polychromatic erythrocytes (MnPCEs) in CGJ-treated mice. Conclusion: CGJ extract elevated the chance that mice would survive a potentially lethal dose of gamma-irradiation. Additionally, The CGJ extract attenuated IL-1β maturation by interrupting the inflammasome. The CGJ extract attenuates radiation-induced micronucleus formation possibly mediated by inhibiting inflammasome, which provides valuable information for the further study of the mechanism of action of CGJ extract.