Single-atom catalysis has gained more and more attention in the field of heterogeneous catalysis in recent years. As the catalytic activity center, uniform and dispersed single atom provides great possibility for the realization of high activity and selectivity of catalytic reaction and to study their catalytic reaction mechanisms. With the gradual decreasing of the catalyst size, the surface atomic structure, electronic structure and defect of catalyst are significantly changed, often resulting in strong metal-support interactions. Based on the previous research works in recent years, the strong metal-support interactions in single-atom catalyst are summarized in this paper. The specific types and forms of strong metal-support interactions in a single-atom catalyst are introduced, including metal-metal interactions, vacancy or defect anchoring, metal cation coordination and organic ligand complexation. Furthermore, based on the understanding and knowledge of strong metal-support interactions in single-atom catalysis, the development trends and key issues in this field are prospected.