Abstract:The polysaccharide of quinoa fermented by Hypsizygus marmoreus mycelium was extracted by a single factor experiment.The antioxidant and α-amylase inhibitory activities of purified and unpurified polysaccharides were determined.The enzymatic hydrolysis-assisted extraction method was better than other methods.The extracted polysaccharide content was（207.67±2.52）mg/g.Four polysaccharide fractions were isolated after purification.Antioxidant and α-amylase inhibition experiments were performed on the unpurified and the purified polysaccharide.Unpurified polysaccharide had the best scavenging effect on DPPH and hydroxyl free radical，with respective inhibition rates of 28.95% and 43.36%；neutral polysaccharide had the most obvious scavenging effect on ABTS free radical with an inhibition rate of 51.22%.Acid polysaccharide-0.1 displayed the most effective inhibition of Bacillus subtilis α-amylase（60.22%）.Acid polysaccharide-0.5 displayed the most significant inhibitory effect on porcine pancreatic α-amylase（50.36%）.The results indicate that polysaccharides obtained from the fermented products of quinoa have antioxidant and α-amylase inhibition activities.The results also provide a basis for studies of the application as functional food additives.