Abstract: Copper is an essential trace element for bacterial metabolism and functions, serving as an electron carrier and cofactor for key enzymes involved in energy generation and redox homeostasis. However, escalating industrial and agricultural activities have intensified environmental copper pollution. Excessive copper induces intracellular reactive oxygen species （ROS） via Fenton-like reactions, causing lipid peroxidation and protein inactivation that severely threaten bacterial survival. This review synthesizes the multi-level defensive networks deployed by bacteria against copper stress. At the individual level, we summarize mechanisms encompassing two-component system-mediated copper sensing, efflux pump-driven export, chaperone-assisted copper homeostasis, and synergistic antioxidant protection. At the community level, we highlight the roles of quorum sensing, biofilm formation, and horizontal gene transfer in enhancing community-wide tolerance. Future research should elucidate habitat-specific regulatory networks governing copper resistance and advance in situ bioremediation strategies utilizing indigenous microbiomes alongside safe and controllable synthetic biology platforms. These endeavors will deepen our understanding of microbial evolutionary adaptation to extreme environments and provide a theoretical foundation for developing effective bioremediation technologies for heavy metal pollution.