In this study, a water-soluble, homogeneous polysaccharide, GDPs-1, was isolated from Gynura divaricata and purified. It was subsequently subjected to structural characterization and biological activity assessment. Structural characterization revealed that GDPs-1 was mainly composed of glucose, galactose, and arabinose, with a molecular weight of 55.1 kDa. Its main structural backbone was →[4)-α-D-Glcp-(1]