The interaction of the metallic surface or nanoparticles with nearby fluorophores broadens the applications of the metallic nanostructures in biological assays and biotechnology, and promotes the development of novel ultrabright fluorescence probes. This paper aims to introduce the mechanism of metal-enhanced fluorescence and its research progress at home and abroad. The factors influencing the efficiency of the fluorescence emission were reviewed, and the unresolved problems and the direction of development in metal-enhanced fluorescence were also present.