Abstract： Objective:To investigate the biological effects of acute high-dose radon exposure on mice.Methods:BALB/c male mice aged 6 to 8 weeks were exposed once in an HD-3 ecological radon chamber with an average radon concentration of 7 × 10 5 Bq/m 3 for 10 h. Mice were weighed, their lung tissues and blood samples were collected at 1, 2 and 3 months after exposure. Control groups were set up at the three time points with four mice in each group. For these mice, the lung tissue pathology was observed using hematoxylin-eosin (HE) staining method, routine blood tests were conducted using a hematology analyzer and the levels of superoxide dismutase (SOD) and malondialdehyde (MDA) in the serum and lung tissues were measured using corresponding assay kits. Results:The HE staining result revealed that compared to the control groups, the experimental groups exhibited thickening of alveolar walls and increased infiltration of granulocyte, whose degrees, however, reduced over time and displayed no significant difference at 3 months after exposure. There was no significant difference in body weight or blood routine between the experimental and control groups. The detection result revealed decreased SOD levels in the lung tissues at 2 months after exposure, which were (11.34 ± 1.03) U/mgprot and (9.75 ± 0.71) U/mgprot, respectively for the control and experimental groups ( t = 2.54, P < 0.05). The MDA levels in lung tissue increased at 1 month after exposure, which were(2.30 ± 0.24) and (2.77 ± 0.29) nmol/mgprot, respectively for the control and experimental groups ( t = 2.49, P < 0.05). At 3 months after exposure, the SOD and MDA levels differed insignificantly between the control and experimental groups ( P > 0.05). Conclusions:After acute high-dose radon exposure, the mice suffered damage to the lung tissue, with changes in their oxidative stress indicators being detected. However, these effects gradually diminished at 3 months after exposure. Additionally, acute high-dose radon exposure did not give rise to significant changes in the body weight or routine blood result of the mice.