Abstract:The Auricularia cornea var. Li. polysaccharide ACP01 was separated from the fruiting body by ceramic membrane. Another polysaccharide ACP02，extracted by the alcohol precipitation method，was used as the control. Their molecular structures，rheological properties，and immunomodulatory activities in vitro were investigated. Structurally，ACP01 and ACP02 were highly branched acidic polysaccharideswith 1，3-Manp and 1，3-Glcp as the main chain and Xyl，Man and Glc glycosidic linkages as side chains. ACP01 exhibited higher purity and lower molecular weight than ACP02. The solutions of ACP01 and ACP02 demonstrated shear-thinning behavior，and higher elastic modulusthan viscous modulus. The gel performance of ACP02 was more stable than that of ACP01 in different concentrations of urea solutions. Regarding biological activity，ACP01 and ACP02 significantly enhanced the production of secreted alkaline phosphatase（SEAP），tumor necrosis factor-α（TNF-α），interleukin-6（IL-6），and nitric oxide（NO）in RAW-BlueTM cells，demonstrating the ability to activate macrophages and exert immunomodulatory functions. The results suggested that the polysaccharide from Auricularia cornea var. Li. had the potential to be developed as an ideal immune modulator and antitumor drug.