The aim of this work is to identify if there is sex specificity on 12C+ ion-induced oxidative damage in mouse lung at different time points.Kun-Ming mice were divided into two groups,each composed of six males and six females:control group and irradiation group with a single acute dose of 4 Gy.Animals were sacrificed at 2,4 and 12 h respectively,there lungs were removed immediately,and the oxidative stress-related biomarkers were measured by Diagnostic Reagent Kits.The results showed that the relative activities of superoxide dismutasc(4 h),catalase(2 h)and Se-dependent glutathione peroxidase(12 h)have significant changes(P＜0.05)between male groups and female groups,suggesting that the lungs of male mice are more sensitive to counteracting the oxidative challenge.Moreover,higher levels of malondiadehyde and lower contents of glutathione were also found in males,indicating that oxidative stress induced by 12C6+ ion is pronounced in the lungs of males.We thought that these sex-responded differences may be attributed to the influence of sex hormones.