Abstract:The content of extracellular polysaccharides and their antimicrobial，antioxidant and inhibitory effects on alpha-amylase of different Morchella strains was investigated. In this experiment，four strains of Morchella esculenta（YS-Y，XH-0，XH-2，XH-4）were used to extract the extracellular polysaccharides from Morchella esculenta by alcohol precipitation method.After removing the proteins by Sevag method，the content of extracellular polysaccharides，their antimicrobial activity，antioxidant capacity and inhibition of alphaamylase were determined，and the results were compared. The results showed that the contents of extracellular polysaccharides of four morel strains of YS-Y，XH-0，XH-2，and XH-4 were 10.05 %，5.80 %，19.89 %，and 8.34%，respectively；four strains of Morchella had certain bacteriostasis ability.The bacteriostasis effect of strain XH-2 was better than that of other three strains，and had the best bacteriostasis effect on Staphylococcus aureus and Escherichia coli. Four strains of Morchella had the ability of reducing，DPPH free radical，ABTS+free radical and hydroxyl radical scavenging.The rate increased with the increase of mass concentration. When the concentration of XH-2 reached 1.0 mg/mL，the reduction ability and ABTS+free radical scavenging ability of strain XH-2 were better than those of other three strains，with OD700 and EC50 of 0.136 and 0.56 mg/mL respectively；DPPH and hydroxyl radical scavenging rate of strain XH-4 were better than those of the other three strains，with EC50 of 16.68 mg/mL and 1.40 mg/mL respectively，and hydroxyl radical scavenging rate of four strains of Morchella XH-2 was higher than VC；inhibition of strain XH-2 on alpha-amylase was stronger than others，its EC50 was 1.55 mg/mL. The research showed that the extracellular polysaccharides of Morchella esculenta had certain biological activity，and strains XH-2 and XH-4 had greater medicinal potential，which could provide some reference for the development of Morchella esculenta resources.