Skin is the largest human organ, inhabited by diverse microorganisms, and most of these microorganisms are harmless or even beneficial to their host. The skin surface is highly variable depending on the characteristics of surface structure and environmental factors, and this drives the variation of skin microbial communities. The development of molecular methods let us know high diversity and variation of microbial communities in human skins, and let us understand skin microorganisms with the perception of skin as an ecosystem. The purpose of this review is to brie?y describe the patterns of skin microbial community and its association with skin diseases, and some of related applications.