Accumulating evidence indicates that gut microbiota dysbiosis is closely associated with the development of colorectal cancer, providing a theoretical basis for microbiota-based interventions. Probiotics, prebiotics, and synbiotics exhibit adjunctive therapeutic potential by modulating microbial composition, improving the mucosal environment, and suppressing inflammation. Certain bacterial strains and their metabolites can directly regulate tumor progression through receptor–signaling pathways, offering a rationale for targeted modulation. In recent years, engineered bacteria, phage therapy, and strategies involving supplementation or antagonism of microbial metabolites have been rapidly advanced, showing promising safety and feasibility in early studies. Despite persistent challenges such as individual variability, limited long-term efficacy, and lack of standardization, multidimensional microbiota-based therapies guided by multi-omics and precision medicine are expected to become an important component of comprehensive colorectal cancer management.