Fungal sclerotium is a dormant structure formed by the branching, interweaving and aggregation of hyphae under the adverse environments, which plays crucially biological and ecological roles in the fungal life cycle and disease cycle. Many devastating plant pathogenic fungi form sclerotia, by which the fungi survive through the adverse environments. Sclerotia germinate and produce apothecia and spores or hyphae that subsequently cause plant infection. Herein, species diversity, biological characterization, melanization, and molecular regulation of sclerotium-forming fungi were comprehensively summarized to provide novel potentials of fungal sclerotia in mycology, plant pathology, and medicinal mycology.