Abstract: Microwave-assisted ethanol immersion extraction was adopted for extracting flavonoids from the leaf of Baoshan Agastacbe rugose and the extraction technology was optimized with single factor experiment and L₉(3⁴)orthogonal design. With the ascorbic acid as the contrast,its reducing power and scavenging activities of ·OH,DPPH·,ABTS⁺· diammonium salt were discussed.The results showed that the optimum condition of flavonoids extraction:Solid-liquid ratio was 1:60 g/mL,ethanol concentration was 60%,microwave power was 567 W and microwave time was 70 s,the extraction could reach to 6.11%. The flavonoids extracted from the leaf of Agastacbe rugose under these conditions had good ability to scavenge several free radicals, especially ABTS⁺·, the IC₅₀ of ·OH,DPPH· and ABTS⁺· was 281.89,3.57 and 1.52 mg/L.