Objective To investigate the therapeutic effects of Isaria felina derived from Cordyceps sinensis combined with cyclophosphamide (CTX) in hepatoma H22 tumor-bearing mice. Methods An H22 tumor-bearing mouse model was established and mice were divided randomly into a normal control group (NC group, distilled water), model control group (MC group, distilled water), positive control group (CTX group, 25 mg / kg), Isaria felina group (IF group,400 mg / kg), and combined administration group (IF + CTX group, IF 400 mg / kg + CTX 25 mg / kg), with 5 mice in each group. Distilled water and IF were administered by gavage, and CTX was administered by intraperitoneal injection.The administration cycle was 10 days. At the end of the experiment, the mean tumor volume and weight, tumor inhibition rate, q value, and immune organ index were calculated, and routine blood indexes and cytokine levels were determined. Histopathological changes in tumor tissues were observed by HE staining. Results The tumor volume and mass were significantly lower in mice in each treatment group compared with those in mice in the MC group (P< 0. 05). The tumor inhibition rates in the CTX, IF, and IF + CTX groups were 49. 3%, 34. 2%, and 72. 8%, respectively, and the q value was 1. 09. The numbers of white blood cells, Lymph, and platelets were significantly higher in the IF + CTX group than in the CTX group (P< 0. 05). The spleen index was significantly higher in the MC group compared with that in the NC group, and significantly lower in the IF + CTX group compared with that in the MC group (P< 0. 05). Serum interferonγ levels were significantly lower in the MC group than in the NC group, and were significantly higher in the IF and IF + CTX groups compared with those in the MC and CTX groups (P< 0. 05). Pathologically, tumor cells in the MC group grew well and were numerous and closely arranged, while cells in the CTX, IF, and IF + CTX groups were arranged loosely, with focal necrosis and nuclear pyknosis of necrotic cells in many places. Conclusions The combination of IF and CTX has an additive anti-tumor effect on H22 tumor-bearing mice, which can alleviate immunosuppression and have an immunomodulatory function.