Bacterial infections are among the greatest threats to human health. However, due to the increasing spread of multidrug-resistant bacteria, the current antibiotic supply appears to be insufficient, thereby necessitating the exploration of novel antibacterial agents. Nano-antibacterial agents represent a new strategy for bacterial treatment. Compared with antibiotics, nano-antibacterial agents have two advantages: (1) broad-spectrum bactericidal effects against Gram-positive and Gram-negative bacteria and (2) long-lasting bactericidal effects due to their extraordinary stability. Significant differences exist in the antibacterial mechanisms between antibiotics and nano-antibacterial agents. Antibiotics can prevent bacterial growth by inhibiting the synthesis of target biomolecules in bacteria, including the cell wall, DNA and proteins. Nano-antibacterial agents kill bacteria through membrane destruction, oxidative stress response, and interactions with cytosolic molecules (lipids, proteins, DNA, etc.).