To examine the relationship between structure and activity of Phyllanthus emblica L. polysaccharides, the polysaccharides were extracted using hot water then precipitated with 50% and 80% (V/V) ethanol into two fractions (PEP-50 and PEP-80). PEP-50 and PEP-80 had the same composition of monosaccharides, but their contents differed to some extent, with galacturonic acid being the main constituent. Besides, the molecular weight of PEP-80 was primarily 234.45 kDa (accounting for 99.21%), which was lower than that of PEP-50 (primarily 256.26 kDa; accounting for 92.51%). Moreover, both PEP-50 and PEP-80 exhibited hypoglycemic activity, with their IC50 values being 3.34 and 0.46 mg/mL, respectively. Both acted as mixed-type inhibitors against α-glucosidase. Compared with PEP-50, PEP-80 exerted a stronger inhibitory effect against α-glucosidase, exhibiting stronger abilities to bind to free α-glucosidase and to α-glucosidase-substrate complex. These differences wereclosely associated with their different chemical compositions and molecular weights. The above experiments suggest that the molecular weight of Phyllanthus emblica L. polysaccharides had a high impact on their hypoglycemic activity, which provides a theoretical basis for future development of healthy foods using different types of Phyllanthus emblica L.