Abstract: The effect of β-Carotene on lipid peroxidation of rat induced by fhxo ride in vitro and in vivo was tudiell by rat liver microscxn al systan and by adding fhxoride(150mg/L）to drinking water In virtro the experinental results showed that fhxoride courd signkfican try increase the content of lipid perxide（LPO)of rat livermicrosomal system, and the lipid peroxidation was an tagonized by adding β-Carotene to rat liverm icroso-malsystan simultaneously. In vivo the experinetal results showed that the LPO lveLs of serum, liver; kindney and heart increased and the GSH-Px and GSH levels decreased in the inple fluoride-treated group This suggested that the ability of the anti-oxidation in fluoriosed rats declined The LPO level of the body w as much lower than the function of antioxidation was considerably improved by adding β-Carotene.