Abstract: Innate immunity is the body's first line of defense against disease. In recent years, a series of studies have shown that the cGAS/STING signaling pathway, an important component of host innate immunity, may play an important role in anti-tumor immunity. cGAS is an innate immune sensor that can recognize abnormal dsDNA in the cytoplasm and activate the STING protein by catalyzing the formation of the second messenger cGAMP, thereby promoting the release of type Ⅰ interferon. The produced type Ⅰ interferon can effectively connect innate immunity and adaptive immunity by promoting the maturation and migration of dendritic cells and enhancing the cytotoxic effect of T lymphocytes or natural killer cells. The cGAS/STING signaling pathway has been confirmed to have anti-tumor effects as well as tumor-promoting effects in the occurrence and progression of tumors. STING agonists have entered clinical trials, and combinations with various treatment modes have also been widely studied. At the same time, nano-drug loading systems have also been developed to achieve stronger anti-tumor effects of STING agonists. This article will review the mechanism of tumor regulation and its application in immunotherapy, so as to provide reference for the development of immunotherapy targeting this pathway.