The extraction， separation and purification methods of polysaccharides from Cardamine hupingshanensis were studied， and simply analyzed its anti-oxidant activity in vitro. The results showed that the optimal process conditions for extracting polysaccharides from Cardamine hupingshanensis by ultrasonic and enzyme were the liquid-to-material ratio of 30∶1， ultrasonic time 25 min， cellulase addition 2%， extraction temperature 90 ℃， extraction time 120 min， the actual value measured was 48.53 mg/g. After 7 times of deproteinization by Svage method， the loss rate of polysaccharide was small， and then DEAE-52 cellulose chromatography to obtain 4 polysaccharides. In vitro antioxidant activity analysis showed that the crude polysaccharides of Cardamine hupingshanensis had a certain reducing ability， and had strong scavenging ability to ABTS radicals and hydroxyl radicals.