[Objective] To investigate the effects of fluoride on catalase (CAT) , lactate dehydrogenase (LDH) , and malonic dialdehyde (MDA) in rat testis and the potential antagonism against these effects by calcium. [Methods] Eighty healthy male SD rats were equally randomized into 10 groups: 1 control group, 6 fluorosis groups with calcium (NaF: 2.1, 4.2, 8.5, 17.0, 34.0, 68.0 mg/kg·d; CaCO3: 25, 50, 50, 100, 100, 150 mg/kg·d, respectively), and 3 fluorosis groups without calcium (NaF: 2.1, 8.5, 34.0 mg/kg·d) . The exposure by intragastric administration lasted 90 days. After the last dosing, sperm count, pathological alternations, and levels of CAT, LDH, and MDA in testis samples were determined. [Results] The fluoride exposure reduced the sperm count and damaged the structure of testis in tested rats. The differences in CAT, LDH, and MDA levels among the experiment groups were statistically significant (F was 5.168, 2.248, 3.168?P < 0.001, 0.044, 0.007, respectively). Compared with the control group, in high-dose fluorosis group treated with 34 mg/kg·d NaF without CaCO3, the level of CAT decreased (27.86±4.04) U/mg prot vs (44.85±2.81) U/mg prot], the level of LDH also decreased [(38 358.49±2 649.23) U/g prot vs (54 357.66±1 903.90) U/g prot], while the level of MDA increased [(6.82±0.79) nmol/mg prot vs (3.59±1.11) nmol/mg prot]. Higher level of CAT and lower level of MDA were observed in the group treated with calcium presented than those in the one with the same dose of fluoride but without calcium. [Conclusion] Fluoride can affect the testis tissue in rats by oxidative stress. The oxidative damage through increasing free radical induced by fluoride may be antagonized by appropriate dose of calcium.