Objective:To study the effects of different doses of X-ray irradiation on the immune microenvironment and cGAS-STING signaling pathway of hepatocellular carcinoma cells.Methods:C57BL/C mice were subcutaneously injected with Hepa 1-6 hepatocellular carcinoma cells in the right axilla to establish a subcutaneous tumor-forming hepatocellular carcinoma model. The mice were randomly divided into 0, 4, 8, 12 Gy irradiation groups, with 10 mice in each group. The body weights and tumor volumes were monitored. Specimens were collected 28 d after irradiation. The ELLSA and Flow Cytometry method was used to compare the macrophage-associated cytokines tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), interleukin-6 (IL-6), chemokine ligand 5 (CCL5), IL-10, IL-13, transforming growth factor-β (TGF-β), IL-4 and macrophage M1, M2 phenotype ratio (M1/M2). Real-time fluorescence quantitative polymerase chain reaction (qRT-PCR) and immunoblotting assay were used to detect the expression of genes and proteins related to the cGAS-STING signaling pathway in hepatoma cells.Results:With the increase of irradiation dose, the tumor volume was significantly reduced ( F=8.42, P<0.05), the proportion of cell necrosis increased ( F=3.89, P<0.05), the content of macrophage-associated cytokines other than IL-4 increased ( F=6.32-15.50, P<0.05), and the proportion of M1 and M2 types of macrophage in the immune microenvironment of hepatocellular carcinoma tumors was elevated ( F= 5.46, 5.14, P < 0.05).The gene expression and protein expression levels of cGAS-STING signaling pathway were elevated in hepatocellular carcinoma cells (mRNA expression of cGAS and STING: F=6.35, 16.10, P<0.05; protein expression of cGAS and STING: F=71.31, 37.15, P<0.05). Conclusions:X-ray irradiation activates the cGAS-STING signaling pathway in hepatocellular carcinoma cells and contributes to the remodeling of the tumor immune microenvironment.