Abstract: Bacillus is a kind of aerobic or facultative anaerobic Gram-positive bacteria, which can produce resistant spores.Bacillus has many species and is featured with strong genetic stability, high temperature and stress resistance.Bacillus is also a kind of important beneficial microorganism, and has many strains with special functions, which can be used to control plant diseases and insect pests, and dissolve non-soluble phosphorus compounds in soils.Moreover, it has a very extensive application value in industry, agriculture and medicine.In this paper, we introduced the classification of main Bacillus species, discussed the mechanisms and functions of different Bacillus species.The existing problems of the Bacillus application in agriculture and its future research avenue were proposed.