Colorectal cancer, as a common malignant tumor, has been increasing in incidence year by year and has become one of the leading causes of death worldwide. Meanwhile, researchers have found a close relationship between dysbiosis of the gut microbiota and colorectal cancer, which has further triggered in-depth exploration of the role of gut microbiota in the pathogenesis, diagnosis, and treatment of colorectal cancer. Studies have shown that there are specific microbial changes in colorectal cancer tissues, including enrichment or depletion of certain bacterial species, which may be associated with tumor growth, invasion, and metastasis. Additionally, gut microbiota has been found to be closely linked to tumor microenvironment, tumor immune response, chemotherapy drug metabolism, and other factors. In this context, it is imperative to study the gut microbiota in colorectal cancer. A comprehensive understanding of the interaction between gut microbiota and colorectal cancer is not only helpful in revealing novel mechanisms of colorectal cancer development, but also holds promise in providing new strategies and targets for early diagnosis, individualized treatment, and prevention of colorectal cancer. This review aims to thoroughly discuss the research progress of gut microbiota in colorectal cancer, including its compositional characteristics, its role in the occurrence and development of colorectal cancer, and its potential clinical applications. The goal is to provide references and insights for further research in this field.