Objective: This study aimed to study the effect of Eurotium cristatum fermentation broth on improving the immunity of immunosuppressive mice. Methods: Immunosuppressive model was established by intraperitoneal injection of cyclophosphamide (80 mg/kg) in mice. Then the immunosuppressive mice were fed with low, middle and high dose fermentation broth for 15 days. The spleen index, carbon clearance test, half hemolysis value (HC₅₀), delayed-type hypersensitivity test and the content of IL-2 in serum were detected to explore the changes of immunological indexes in immunosuppressive mice treated with fermentation broth. Results: Compared with the model group, the fermentation broth of the middle and high dose groups could significantly enhance the half hemolysis value (P＜0.05) and delayed hypersensitivity (P＜0.05) of immunosuppressive mice. Moreover, the fermentation broth of the low, middle and high dose groups could increase the content of IL-2 in serum, which was 3.07, 3.10, 2.87 times that of the regular group, respectively, but had no significant effect on the immune function of monocytes and macrophages in mice. Conclusion: E. cristatum fermentation broth could enhance the immunity of mice.