Objective : To explore the therapeutic effect of extracellular vesicles(EVs) of Aspergillus flavus(A. flavus) on A. flavus infection. Methods: The EVs of A. flavus were isolated using ultracentrifugation and detected/identified by nanoparticle tracking analysis(NTA). Quantitative real-time PCR(qRT-PCR) and enzyme-linked immunosorbent assay(ELISA) kits were used to assess the effect of A. flavus EVs on the polarization of bone marrowderived macrophages(BMDMs) and the expression levels of several cytokines,including tumor necrosis factor-α(TNF-α),interferon-γ(IFN-γ),interleukin-6(IL-6),and interleukin-10(IL-10). The Galleria mellonella(G.mellonella) infection model was constructed. Three concentration groups of A. flavus EVs(0. 2,2,and 20 μg/larvae) were set as the experimental groups,and PBS was used as the control group for the infection model.Meanwhile,three forms of negative control groups were established,including the PBS group,the pierced controlgroup, and the negative control group. The therapeutic effect of A. flavus EVs on A. flavus infection was evaluated by the survival rate of the G. mellonella infection models. Results: The particle size of A. flavus EVs ranged from 20 to550 nm. A. flavus EVs could polarize BMDMs into both M1 and M2 phenotypes and induce the production of cytokines,including TNF-α,IFN-γ,IL-6,and IL-10. The results of the G. mellonella infection model showed that A.flavus EVs could improve the survival rate of G. mellonella after A. flavus infection. Conclusion The EVs produced by A. flavus can promote the expression of both pro-inflammatory and anti-inflammatory cytokines in BMDMs,induce M1 polarization and M2 polarization of BMDMs,and increase the survival rate of G. mellonella after A. flavus infection.