Bacterial infectious diseases caused by microecological imbalance pose serious threats to human health, while conventional bacteriostatic strategies often suffer from limitations including imprecision and the emergence of antibiotic-resistant bacteria. In this study, bacterial extracellular vesicles (EVs), derived specifically from S. aureus, are applied to construct a stable implant coating mediated by poly (tannic acid) (pTA). The resultant EVs coating, functioning akin to a “spear and shield”, possesses the ability to autonomously discriminate between non-parental bacteria (N-bacteria) and parental bacteria (P-bacteria), bestowing implants with accurate and selective adjusting capacities in vitro and in vivo. Within this construct, the EVs coating of gram-positive bacteria alters bacterial metabolism and membrane transport, affecting gene mismatch repair. For N-bacteria, the EVs coating acts like a sharp spear, effectively combating their growth. Conversely, it functions as a protective shield, precisely fostering the growth of P-bacteria. The TA-mediated EVs coating provides a research basis for advancing research in microecological control of infectious diseases and the treatment of other diseases associated with microecological imbalances.