Abstract: To investigate the immune regulation and antioxidation effects of polysaccharide from Ilex kudingcha C.J. Tseng on mouse spleen lymphocytes in vitro. The proliferation, antioxidant capacity (SOD, T-AOC, GSH-Px and CAT) activity and malonic dialdehyde (MDA) content, as well as the secretion of cytokines (TNF-α, IFN-γ and IL-1β) were detected after treating with polysaccharide from Ilex kudingcha C.J. Tseng. The results showed that polysaccharide from Ilex kudingcha C.J. Tseng could promote the proliferation of spleen lymphocytes dose-dependently. Compared to the OD value of control group (0.31), the OD values at the concentration of 80 and 160 μg/mL were increased significantly (P<0.01) to 0.38 and 0.41, respectively. The activities of SOD, T-AOC, GSH-Px and CAT were increased with increasing concentration of polysaccharide from Ilex kudingcha C.J. Tseng. And there were significant differences (P<0.01) between control group and 160 μg/mL polysaccharide from Ilex kudingcha C.J. Tseng group, the activities of SOD, T-AOC, GSH-Px and CAT were of 4.54 U/mg protein, 1.06 mmol/mg protein, 799.01 mU/mg protein and 806.85 U/mg protein, respectively. Meanwhile, compared to control group, polysaccharide from Ilex kudingcha C.J. Tseng could significantly decrease the contents of MDA, increase NO production and promote the secretion of TNF-α, IFN-γ and IL-1β. In conclusion, the immunomodulatory effect of polysaccharide from Ilex kudingcha C.J. Tseng may be related to the promotion of splenic lymphocyte proliferation, the enhancement of antioxidant activity and the induction of cytokine secretion level. The results are beneficial to provide a theoretical basis for the development and utilization of Ilex kudingcha C.J. Tseng.