Abstract: Objective:To investigate the immunomodulatory function of jackfruit oligopeptides(JOPs). Methods:SPF female BALB/c mice were used as experimental subjects,and 8 immunoassays were performed to systematically evaluate the effect of different intervention doses' JOPs(0.20,0.40,0.80 g/kg·bw)on relative weight of immune organ,relative weight,cellular immune function,humoral immune function,mononuclear-macrophage function,natural killer cell(NK cell)activity and the T lymphocyte subsets in mice. Results:Compared with the blank control group,the spleen index in the 0.40,0.80 g/kg·bw dose group of JOPs was significantly increased(P<0.05),and the spleen index of the JOPs 0.40 g/kg·bw dose group was significantly higher than that of the whey protein group(P<0.05). Compared with the blank control group as well as the whey protein group,the proliferation of spleen lymphocytes induced by ConA,the degree of footpad thickening,the number of hemolytic plaques,the carbon clearance phagocytosis index(a),The macrophage phagocytic rate as well as phagocytic index and NK cell activity of macrophages in the 0.40,0.80 g/kg·bw dose group of JOPs were significantly increased(P<0.05). Compared with the blank control group as well as the whey protein group,the serum hemolysin content,the number of CD3⁺T cells,the percentage of CD4⁺T cells and the ratio of CD4⁺CD25⁺/CD4⁺ and CD4⁺/CD8⁺ in the 0.80 g/kg·bw group of JOPs were significantly increased(P<0.05). There was no significant effect on the weight gain and thymus index of the mice in each dose group of JOPs(P>0.05). Conclusion:JOPs can strengthen the immune function by improving the function of body's adaptive and innate immunity.