Abstract: AIMTo study the effect of Angelica sinsensis polysaccharides on lymphocyte proliferation and induction of IFN-γ. METHODSAngelica sinensis polysaccharides(AP) were separated into AP-I, AP-II, AP-III and AP-IV by alcohol deposition with different concentration. The radioactivities of ［3H］-TdR uptake by lymphocyte were used to determine the ability of lymphocyte. The bioactivity of IFN-γ was measured by violet crystalline dying. RESULTSAP-IV was found to be composed of Ara and Glu in the ratio of 0.99∶6.47, the molecular weight was estimated to be 5 600. AP-I and AP-II 100 mg·kg^-1 ip were found to significantly augment mice splenocyte proliferation, release IFN-γ and increase IFN-γ bioactivity. 50 μg·mL^-1 AP-I, AP-II and AP-III were shown to enhance the proliferative response of the mouse spleen lymphocytes in vitro. CONCLUSIONAP-I and AP-II showed higher immunoactivity than AP-III, AP-IV had no effect.