<p>Bacteria, as simple unicellular microorganisms, can directly lyse tumor cells following intratumoral administration. Flagellin and cell wall components derived from bacteria can reshape the tumor microenvironment and activate host anti-tumor immune responses. Notably, certain anaerobic and facultative anaerobic bacteria exhibits preferential colonization in the hypoxic core of solid tumors, where they can serve as in situ “micro-bioreactors” and targeted delivery vectors for synergistic tumor therapy. Based on rapid advances in synthetic biology, diverse engineered bacteria and bacteria-based biohybrid systems have been developed for precision tumor therapy, including gene restoration, environment-responsive programmable expression, cytotoxic protein production, and multimodal combination therapy with nanomaterials, immune modulators, or photothermal agents. These living platforms enable targeted drug/gene delivery, sustained local therapeutic output, and durable anti-tumor immune activation. However, clinical translation remains hindered by insufficient biosafety control, off-target colonization, uncontrolled proliferation, immune clearance, and lack of standardized manufacturing and regulatory guidelines. This review systematically summarizes the historical development, inherent anti-tumor mechanisms, genetic engineering strategies, and multimodal biohybrid systems of bacteria-mediated tumor therapy. We comprehensively discuss the advantages, limitations, comparative characteristics, and core bottlenecks of different platforms, and propose rational design strategies for next-generation intelligent, controllable, and clinically translatable bacteria-derived living anti-tumor systems.</p>