Polysaccharides are the important biologically active components found in the peel of Dioscorea opposita Thunb. (DTTP). The influences of 4 extraction methods, namely hot water extraction (W), acidic extraction (HA), hot-compressed water extraction (HCW) and enzyme-assisted extraction (EAE), on the yields, physicochemical properties, hypoglycemic and antioxidant activities of polysaccharides from DTTP were studied and compared. Among these DTTP polysaccharides, DTTP-HA was outstanding in several respects. DTTP-HA was the most water soluble; it had the highest total carbohydrate content (85.08%), the highest uronic acid (13.20%) and the highest thermal stability. DTTP-HA and DTTP-W possessed a triple-helix structure. These 4 kinds of polysaccharides have the same types of monosaccharides, but in different molar percentages. Extraction method had a significant impact on the microstructures of the extracted polysaccharides. DTT-HA exhibited irregular structure with many holes. Among the 4 extracted methods, the DTTP-HA and DTTP-W initially exhibited higher hypoglycemic and antioxidant activities. The better bioactivities of DTTP-HA may be related to the above factors. The findings indicated that acid extraction is an effective method to extract polysaccharides with high biological activities from DTTP.