Microbes appear in every coer of human life,and microbes affect every aspect of human life.The human oral cavity contains a number of different habitats.Synergy and interaction of variable oral microorganisms help human body against invasion of undesirable stimulation outside.However,imbalance of microbial flora contributes to oral diseases and systemic diseases.Oral microbiomes play an important role in the human microbial community and human health.The use of recently developed molecular methods has greatly expanded our knowledge of the composition and function of the oral microbiome in health and disease.Studies in oral microbiomes and their interactions with microbiomes in variable body sites and variable health condition are critical in our cognition of our body and how to make effect on human health improvement.