To optimize the extraction of total flavonoids from Senecio dianthus Franch.and determine their antioxidant activity.Using an orthogonal design with single-factor experiments,the effects of refluxing temperature,extraction time,liquid-solid ratio and ethanol concentration were investigated to optimize the extraction.The reducing effect of total flavonoids and ability to eliminate ·OH were also investigated by the method of Fenton and Smirnoff.The optimum extraction conditions were as follows: reflux temperature 90 ℃,extraction time 2 h,liquid-solid ratio 30 ∶ 1,and ethanol concentration 70%.The flavonoids extracts in the scavenging ·OH was highly effective in the certain concentration range.The extracting method was optimized,and the total flavonoids had strong antioxidant activity in the certain concentration range.