Abstract: An experiment was conducted to investigate the effect of botanical fluorine from Potamogoton pectinatus on antoxidation system and production performance of Mongolian sheep. Botanical fluorine with 0、50、100、150 mg/kg in daily ration was used to feed the Mongolian sheep for 5 months, and weight gain and serum antioxidase of Mongolian sheep was measured at the 15 days. This study indicated that Mongolian sheep was not found to be fluorosis toxicosis. The weight gain, serum superoxide dismutases, glutathione peroxidase, serum total antioxidant capacity were not different between Mongolian sheep fed with P.pectinatus and Mongolian sheep fed with Sorghum hybrid Sudangrass. This study suggested that P.pectinatus did not affect the production performance of Mongolian sheep.