The species or varieties as well as planting area of genetically modified plants,especially Bt transgenic crops for insect resistance have increased rapidly worldwide in the past decade.The environmental risk assess of Bt transgenic crops is the focus that have paid much attention to.Arbuscular mycorrhizal fungi(AMF) are kind of ubiquitously exited soil microbe,which play important roles in soil ecosystem by combining root with the majority of plant species.How Bt transgenic crops affect AMF is a crucial problem that should be solved in future.In this paper,the published data about above issue were summarized,and the harmful mechanisms according to Bt toxins occurrence and distribution were put forward.Furthermore,an opinion of planting in large scale of Bt transgenic crops will influence biodiversity of AMF were put forward.