Abstract: Polysaccharides were extracted from Gynura procumbens with distilled water as solvent in this article.Extraction temperature,extraction time,solid-liquid ratio and microwave power were chosen as four main influence factors,and then extraction conditions were optimized by orthogonal test.The results indicated that the influence level of them was extraction time > microwave power > extraction temperatures > solid-liquid ratio,respectively.The optimal extraction conditions were proved to be extraction temperature of 70  ℃，extraction time of 70 min，solid-liquid ratio of 1∶14 (g/mL) and microwave power of 600 W by the orthogonal test and its verification test.Under this condition，the yield of Gynura procumbens polysaccharides was 12.2%.In the range of 1.0-5.0 mg/mL，the antioxidant activities increased with an increase of mass concentration．At the mass concentration of 5 mg/mL，the total antioxidant activity was (11.76±0.45) U/mL and reached more than that of 94% Vc with the same mass concentration．The scavenging effects on DPPH free radical and OH free radical in different concentration reached more than those of 90% of Vc with the same mass concentration．The scavenging effect on H₂O₂ reached more than that of 60% Vc with the same mass concentration.

Key words: gynura procumbens, polysaccharides, extraction condition, antioxidant