[en] In this study, a charge-conversion mechanism was introduced into the design of a bacteria-responsive antibacterial surface. The antibacterial surface was facilely constructed via surface tethering of antimicrobial peptides (AMPs) to solid supports and subsequently integrating charge-conversion moieties into the peptide structure. The resulting zwitterionic structure of the AMPs rendered the antibacterial surface biocompatible under normal physiological conditions. Importantly, the surface exhibited self-defense properties specifically against pathogenic bacteria; the toxicity of AMPs was activated in bacterially induced acidic environments. Unlike previously described self-defense systems that utilize an antimicrobial release mechanism, this antibacterial surface exerts its bactericidal effects by diminishing the nonbactericidal masking moieties and activating the surface-tethered AMPs to avoid the undesirable toxic effects caused by planktonic AMPs. In contrast to the prevailing passive switchable antibacterial surfaces, our surface uses a unique self-adaptive zwitterionic-to-cationic transition mechanism to inhibit the development of bacterial infections.