The invention relates to the technology of microbial insecticides and aims to provide bacillus amyloliquefaciens HZ179 and an application thereof in preparation of a microbial insecticide. The bacillus amyloliquefaciens HZ179 is preserved in CGMCC (China General Microbiological Culture Collection Center), and the preservation number is CGMCC No: 11358. Compared with the prior art, the bacillus amyloliquefaciens HZ179 has the benefits as follows: the strain has remarkable toxic action on aphids, the effective ingredient of the insecticide is the bacillus amyloliquefaciens HZ179 and is non-toxic for people and livestock, and compared with a chemical pesticide, the insecticide has the characteristic of safety. The microbial insecticide can be prepared with a microbial fermentation technology; a fermentation medium adopts common agricultural byproducts as main ingredients, the fermentation period is shorter, and accordingly, the production cost is lower.