Abstract: Objective　To investigate the effects of CeO2NP subacute exposure on body weight, organ structures, and redox indicators in male mice. Methods 　Thirty-five male ICR mice were randomly divided into five groups with seven mice in each group. Normal control and CeO2NP (100, 500, 1000 and 5000 μg/ kg)groups were included. Mice were injected with CeO2NPs intraperitoneally every other day for 28 days. Results 　Compared with the control group, no significant difference was found in weight gain (P>0. 05), but significant differences were observed in the liver coefficient, epididymal coefficient, and sperm survival rate (P<0. 01). In the 5000 μg/ kg group, CeO2NPs were deposited in the liver and spleen, and granuloma was found SOD and GSH-Px activities in serum of the 100 μg/ kg group were increased, while MDA content was decreased, which indicated the antioxidant effect of CeO2NPs. With the increase in dose, oxidative stress induced by CeO2NPs was enhanced. Conclusions　Low-dose-CeO2NPs are safe and exert an antioxidant effect. With the increase in dose, the toxicity of CeO2NPs also increases gradually.