〔Abstract〕 Objectivec To investigate the therapeutic effect of wall-broken Ganoderma lucidum spore powder (GLS) on a mouse model of hepatocellular carcinoma and to explore its underlying mechanism. Methods Fifty 14-day-old C57BL/6J mice were divided into a control group, a model group and low, medium and high-dose GLS groups(0.25, 0.5, 1.0 g/kg ), with 10 mice in each group. A DEN/CCL4 mouse hepatocellular carcinoma model was established, and GLS was administered by gavage starting from the 8th week, once a day for 14 weeks. At the end of the final administration, the number of liver nodules was observed , and the serum alpha-fetoprotein (AFP) was detected using enzyme-linked immunosorbent assay. The content of catalase (CAT) in serum and liver tissue was determined by ammonium molybdate method. The content of reduced glutathione (GSH) in serum and liver tissue was measured by microplate assay. The content of glutathione peroxidase (GSH-PX) in serum and liver tissue was detected by colorimetric method. Immunohistochemistry (IHC-P) was employed to detect the protein expression of proliferating cell nuclear antigen (PCNA). R eal-time fluorescence quantitative polymerase chain reaction was utilized to detect the relative expression of nuclear factor E2-related factor 2 (Nrf2), Kelch-like epichlorohydrin-associated protein 1 (Keap1),NAD(P)H quinone oxidoreductase 1 (Nqo1), heme oxygenase-1 ( Ho-1 ) and glutamate cysteine ligase catalytic subunit (Gclc) mRNA. Results Compared with the control group, the content of serum AFP were significantly higher in the model group (P<0.01), while the contents of CAT, GSH and GSH-PX in liver and serum were significantly lower in the model group (P<0.01). The relative expression of Keap1 and Nqo1 mRNA was significantly higher (P<0.01), the relative expression of Nrf2, Ho-1, Gclc mRNA relative expression was significantly lower (P<0.01), and the positive expression rate of PCNA was significantly higher (P<0.01). Compared with the model group, the total number of liver nodules and content of serum AFP in the administered group were significantly lower (P<0.01), and the contents of CAT, GSH, and GSH-PX in the liver and serum of mice significantly increased (P<0.05 or P<0.01). The expression of Keap1 and Nqo1 mRNA significantly decreased (P<0.05). The expression of Nrf2, Ho-1 and Gclc mRNA significantly increased (P<0.05), and positive expression rate of PCNA significantly decreased (P<0.01). Conclusion GLS has a significant protective effect on DEN/CCL4 -induced mouse hepatocellular carcinoma model, and the mechanism of action is related to the regulation of oxidative stress in mouse liver.