Abstract: To investigate the immune regulatory effects of Asparagus cochinchinensis polysaccharide (ACP) on immunosuppressed mice, a total of 60 Kunming mice weighing 18-22 g were randomly assigned into the following six groups: a saline control group (n=10) received no treatment, a positive control group (n=10) received intraperitoneal injection of 150 mg/(kg·BW) cyclophosphamide, and four drug intervention groups (n=10 in each group) received administration of 100, 200, 300 and 400 mg/(kg·BW) ACP solution after intraperitoneal injection of 150 mg/(kg·BW) cyclophosphamide, respectively. After the administration for 7 consecutive days, the plasma levels of cytokines including IL-2, IL-6 and IFN-γ of the mice in different groups were determined and compared. Furthermore, the spleen index and thymus index were calculated, and the histological changes of the spleen and thymus were observed. The results showed that the 100 and 200 mg/(kg·BW) ACP intervention groups had obviously higher plasma levels of IL-2 and IL-6 compared to the saline control group and cyclophosphamide control group;the plasma level of IFN-γ in 200 and 300 mg/(kg·BW) ACP intervention groups were significantly elevated;the mice treated with different doses of ASP had a significantly higher spleen index. The results indicated that ACP could enhance the immune function of mice.