Ophiocordyceps contains the largest number of Cordyceps sensu lato , various species of which are of great medicinal value. In this study, a new entomopathogenic fungus, Ophiocordycepsnujiangensis , from Yunnan in southwestern China, was described using morphological, phylogenetic, and mitogenomic evidence, and its fungal community composition was identified. It was morphologically characterized by a solitary, woody, and dark brown stromata, smooth-walled and septate hyphae, solitary and gradually tapering conidiogenous cells with plenty of warty protrusions, and oval or fusiform conidia (6.4-11.2 × 3.7-6.4 µm) with mucinous sheath. The phylogenetic location of O.nujiangensis was determined based on the Bayesian inference (BI) and the maximum likelihood (ML) analyses by concatenating nrSSU, nrLSU, tef-1a , rpb1 , and rpb2 datasets, and ten mitochondrial protein-coding genes (PCGs) datasets ( atp6 , atp9 , cob , cox2 , nad1 , nad2 , nad3 , nad4 , nad4L , and nad5 ). Phylogenetic analyses revealed that O.nujiangensis belonged to the Hirsutellasinensis subclade within the Hirsutella clade of Ophiocordyceps . And O.nujiangensis was phylogenetically clustered with O.karstii , O.liangshanensis , and O.sinensis . Simultaneously, five fungal phyla and 151 fungal genera were recognized in the analysis of the fungal community of O.nujiangensis . The fungal community composition differed from that of O.sinensis , and differences in the microbial community composition of closely related species might be appropriate as further evidence for taxonomy.