Fusarium mycotoxins, commonly present in corn and its derived products for animals, has caused significant economic impact on swine reproduction in the People’s Republic of China. The objective of the present study, therefore, was to evaluate changes in mycotoxin contents and microbial diversity by conventional solid fermentation of a contaminated diet. Three diets were evaluated, as follows: control group, basal diet; test group 1 (25 Toxin), basal diet in which corn and corn gluten meal were replaced with 25% mycotoxin-contaminated corn and corn gluten meal, respectively; test group 2 (50 Toxin), basal diet in which corn and corn gluten meal were replaced with 50% mycotoxin-contaminated corn and corn gluten meal, respectively. Compound strains were used for solid-state fermentation of the compound feed. Under the present experimental conditions, conventional solid fermentation altered microbial diversity, as demonstrated by high-throughput sequencing of a Fusarium mycotoxin-contaminated diet, and the content of zearalenone (ZEA) was reduced significantly. However, deleterious effects were also observed with regard to the contents of deoxynivalenol (DON) and fumonisin B₁ (FUMB₁). These results may have implications for animals consuming Fusarium mycotoxin-contaminated food or feed by conventional solid fermentation.