Aflatoxin, with strong toxicity, is a group of secondary metabolites produced by the Aspergillus flavus, Aspergillus parasitieus and some other fungies. Aflatoxin can lead to liver enlargement, diseases and even cancer, showing a great threat to humans and animals health. This article introduces the molecular structure, physical and chemical properties, pollution situations of aflatoxin B1. Research progress about the biological detoxication especially microbiological degradation of aflatoxin B1 and application are discussed.