Fluorescent metal nanoclusters（MNCs）,as novel fluorescent materials,exhibit good biocompatibility and excellent physicochemical properties,which have attracted more and more attention in various fields,especially in the biomedical field.In this review,the synthesis methods and optical properties of various metal nanoclusters are described.Then,the applications of metal nanoclusters in the biomedical field are reviewed from three aspects of biosensing,bioimaging and cancer therapy.Finally,the future challenges and application prospects of the MNCs in biomedical application are discussed.