Abstract: To reveal the diversity of mycoviruses in Stagonosporopsis cucurbitacearumstrains and investigate their biological characteristics, metaviromic analysis and biological characterization were performed on 12 Stagonosporopsis cucurbitacearumstrains isolated from tobacco leaf spot-infected samples collected in Sanming, Fujian Province. The results showed that: ① Metaviromic analysis identified 13 viral contigs, which, after comparative analysis, were determined to belong to 12 distinct viruses, including 2 dsRNA viruses and 10 +ssRNA viruses. Among these, 7 viral contigs exhibited low homology with known viruses, suggesting they may represent potential novel viruses. ② Phylogenetic analysis classified these 12 viruses into 7 distinct families: Mitoviridae, Botourmiaviridae, Partitiviridae, Narnaviridae, Deltaflexiviridae, Fusariviridae, and Totiviridae. ③ Biological characterization revealed that two strains (M-2 and M-8 ) exhibited significantly reduced growth rates, abnormal colony morphology, decreased pigment production, and markedly attenuated pathogenicity. This study represents the first report on the diversity of mycoviruses in Stagonosporopsis cucurbitacearum, expanding the known diversity of mycoviruses. Furthermore, the identification of two hypovirulent strains provides valuable resources for the subsequent characterization of hypovirulence-associated mycoviruses and their potential application as biological control agents against diseases caused by Stagonosporopsis cucurbitacearum.