Abstract: Extraction and purification of polysaccharides from the seed kernel of Acer truncatum Bungeto investigate their physicochemical properties and hypoglycemic activity. In the study, the polysaccharide was obtained by water extraction and ethanol precipitation from seed kernel of Acer truncatum Bunge, and the extraction process was optimized by response surface method. The polysaccharide was purified by Sevage deproteinization and column chromatography. The composition and structure of the purified polysaccharide were characterized by infrared spectroscopy, thermogravimetric analysis and ion chromatography, and its hypoglycemic activity was further investigated by the insulin resistance model of liver cancer cell (IR-HepG2). The results showed that the yield of crude polysaccharide (PATM) was 18.17% under the conditions of extraction times 1, liquid-solid ratio 30:1 mL/g, extraction temperature 80 ℃ and extraction time 3.5 h. The purified polysaccharide (PATM-3-1) obtained by the Sevage deproteinization, DEAE-DE cellulose 52 column and SephadexG-100 gel column had the characteristic peak of infrared spectrum of polysaccharide component, and was composed of D-galacturonic acid, L-arabinose, D-galactose, L-rhamnose, D-glucose, D-xylose, D-mannose, D-glucuronic acid, L-fucose, D-ribose and D-glucosamine. The results of hypoglycemic activity experiment in vitro showed that PATM-3-1 had strong α-amylase inhibitory activity, and could significantly (P<0.05) increase the glucose consumption, glycogen content, hexokinase content and pyruvate kinase content in IR-HepG2, demonstrating excellent hypoglycemic activity. This study would provide data support for the development and application of seed kernel polysaccharide from Acer truncatum Bunge.