In this manuscript, polysaccharide (TMSP) was isolated from Trichosanthes kirilowii Maxim. seed shell. The homogeneous polysaccharide (TMSP-1; molecular weight: 690.239 kDa) was purified by column chromatography (DEAE-cellulose-52 and Sephadex G-150). The result of monosaccharide composition showed that TMSP-1 consisted of D-mannose, D-glucose, D-galactose, and glucuronic acid in a molar ratio of 2.01 : 1.98 : 1.87 : 1. Methylation analysis showed that TMSP-1 was made up of →3)-D-Galp-(1→, D-Glcp-(1→, →4)-D-Manp-(1→, →6)-D-Galp-(1→, →4)-D-Galp-(1→, and →4,6)-D-Manp-(1→. The microscopic conformation of TMSP-1 showed a regular flake-like structure that was inlaid with small holes. The α-glucosidase inhibitory rate of TMSP-1 reached 52.23% when the concentration of TMSP-1 was 8 mg/mL, which confirmed the potential hypoglycemic activity of TMSP-1 in vitro. In vivo results showed that type 2 diabetes causes a significant increase in organ index and TMSP-1 recovered the organ index in mice (P < 0.05). Furthermore, TMSP-1 reversed the increase of liver and kidney weight and the indicators of abnormality. This research lays a foundation for research on the polysaccharides of Trichosanthes kirilowii Maxim. seed shell in hypoglycemia. [ABSTRACT FROM AUTHOR]