Abstract: Polysaccharides are important constituents of Lanzhou lily bulbs and have been associated with the regulation of glucose metabolism. To characterize the physicochemical properties and in vitro hypoglycemic potential of a polysaccharide fraction (LLP) isolated from the bulbs of six-year-old Lanzhou lily (Lilium davidii var. willmottiae), LLP was prepared by hot-water extraction and ethanol precipitation, followed by Sevag deproteinization and Sephadex G-100 column chromatography. The physicochemical characteristics of LLP were characterized by high-performance liquid chromatography (HPLC), Fourier transform infrared spectroscopy (FT-IR), the Congo red assay, scanning electron microscopy (SEM), and thermogravimetry–differential scanning calorimetry (TG–DSC). Its hypoglycemic potential was evaluated using α-glucosidase and α-amylase inhibition assays and an insulin-resistant HepG2 cell model. LLP was found to have a relative molecular mass of approximately 1.15×10? Da. It was composed of mannose (Man), galacturonic acid (GalA), glucose (Glc), galactose (Gal), and arabinose (Ara) at a molar ratio of 15.42:0.62:83.67:0.14:0.15. Typical infrared absorption bands of polysaccharides were observed; its aqueous solution was suggested to possess a helical conformation, its microstructure was characterized by rough and loose lamellae, and it was relatively stable below 147.40 °C. The IC?? values of LLP against α-glucosidase and α-amylase were determined to be 0.82 and 1.49 mg·mL?¹, respectively. At 100.00 μg·mL?¹, glucose consumption in HepG2-IR cells was significantly increased compared with that in the model group (P<0.05). Thus, typical physicochemical characteristics of polysaccharides and in vitro hypoglycemic activity were observed for LLP, providing a theoretical basis for its development as a functional food ingredient.