The problem of healthcare-assocaited infection (HAI) and multidrug-resistant organism persists, but the role of antimicrobial agents is gradually weakened. Among many new antimicrobial agents, nano-selenium has relatively low toxicity and strong antimicrobial efficacy. Therefore, this paper introduces nano-selenium materials from three aspects: antimicrobial activity and its influencing factors, antimicrobial mechanism, and research progress of improved nano-selenium materials, elaborating and looking forward to the clinical application of nano-sele-nium, so as to provide reference for its research and application in antimicrobial field.