Abstract: Objective To investigate the mechanism of renal impairment induced by fluoride.Methods The rats were freelyadmin istered with low,medium,and high concentration of NaF.The rats were sacrificed 9 months after the treatment,and the oxidation level and nuclear factor B(NFB)expression level in kidney were determined.Results The malondial dehyde contents and the activity of glutathione peroxidase of low dose and high dose groups were obviously higher than that of the control group(P<0.05).There was a non significant downward trend inactivity of superoxide dismutase(P>0.05).The NFB expression level increased with the exposure dose compared with that of the control group with an obvious increase in the high dose group(P<0.05).Conclusion Chronic fluorosis can causeoxidative damage of kidney tissue.