Abstract: To study antioxidant activity of medlar honey,the total phenolic contents,total flavonoids contents and antioxidant activity in vitro of medlar honey from Qinghai province were determined. Protective effect of medlar honey on the oxidative damage of DNA induced by hydroxyl radicals was examined by comet electrophoresis. The results showed that medlar honey possessed capability to effectively remove free radicals and strong antioxidant activities. The antioxidant activity of medlar honey was related to its total phenol contents(p<0.05),while the ferrous ion-chelating activity of medlar honey correlated with it’s total flavonoids contents. The results of comet electrophoresis showed that the DNA oxidant damage of mice lymphocytes induced by hydroxyl radicals was prevented by medlar honey. Compared to model group,the percent of DNA in the comet tail,tail moment and olive tail moment of experience group all significantly reduced(p<0.05)in a dose-dependent manner. The determinant coefficient of linear regression equation between the percent of DNA in the comet tail,tail moment,olive tail moment and concentration of medlar honey were R²=0.9775,R²=0.9341 and R²=0.9425,respectively. This study would provide a basis for the development and utilization of medlar honey as functional food.