Abstract:The term “microorganism” refers to tiny organisms such as archaea, bacteria, protists, fungi, and viruses, and the term “microbiome” refers to a collection of microorganisms. Although they share the body space of the host, their roles as determinants in host health and diseases are ignored. As a collection of information, the microbiome includes the genomic data, structural elements, metabolites, and environmental conditions of microorganisms. Studies have demonstrated that the microbiome plays an essential role in maintaining host homeostasis and regulating host phenotypes. With the advent of new technologies, including next-generation sequencing (NGS) and sequencing-based microbiome profiling, researchers have probed into the relationship between the microbiome and host phenotypes. By an overview of microbiome, this paper elaborated on the microbiome-host genetics interactions based on genome-wide association analysis and made an outlook on the future of this field.