To estimate accurately biological dose of the victims exposed to high dose, the dose-response curves of chromosome aberration induced by 6—22Gy ,60,Co γ-ray were established. Human peripheral blood in vitro was irradiated, then lymphocytes were concentrated, cultured 52h, 68h and 72h and harvested. The frequencies of dicentrics (multi-centrics) and rings were counted and compared between different culture times The dose-response curves and equations were established, as well as verified with high dose exposure accidents. The experiment showed that the culture time should be prolonged properly after high dose exposure, and no significant differences were observed between 52—72h culture. The dose-response curve of 6—22Gy fitted to linear-square model ,Y,=-2.269+0.776D-7.868 ×10,-3,D,2, and is reliable through verification of the accident dose estimations. In this study, the dose-response curve and equation of chromosome dic+r after 6—22Gy high dose irradiation were established firstly, and exact dose estimation can be achieved according to it.