Abstract: Through the preparation of the crude polysaccharide(SGP-C)from Sarcandra glabra(Thunb)Nakai, the polysaccharide of SGP-O was obtained with optimal purification conditions(pH 9, 5% H₂O₂, 50 °C, decolored for 3. 5 h). Then, high-quality polysaccharide(SGP-2)was purified by Sephacryl S-400 molecular sieve with the yield of 0. 35%. In vitro α-glucosidase inhibition assay indicated that SGP-2 had an IC₅₀ of(87. 06±11. 76)μg/mL, only a quarter of that of acarbose(338. 9±46. 86 μg/mL), which indicated that SGP-2 had strong α-glucosidase enzyme inhibitory activity. Preliminary dynamic studies showed that SGP-2 inhibited α-glucosidase in a reversible and mixed-type mode.