The invention discloses a fungal strain of the genus Aspergillus and its application, and the fungal strain of the genus Aspergillus is classified as Aspergillus nomius , Deposit unit: General Microorganism Center (CGMCC) of China Microbiological Culture Collection Management Committee (CGMCC), deposit date: December 28, 2018, deposit number: CGMCC No.17066, the fungus of the genus Aspergillus belongs to the Kingdom Mycophyta, Phylum Fungi, Silk Sporina, Hyphospora, Leucospora, Aspergillus. The application is the application of the Aspergillus fungus strain in the preparation of biological preparations for biological control of red imported fire ants.