A rarely large-scale metazon framework is developed widely in Bianping Village, Houchang Town, Ziyun County, South Guizhou Pronince in the Carboniferous Period. The Bianping reef is constructed mostly by big phacelloid Fomithevella and its basement is composed of patch reefs, thus, forming a unique type of the Carboniferous Bianping reef. Detailed research on the reef-building communities, especially Fomithevella communities, shows that biologic and physical structures of the communities play decisive roles in constructing overall structure of reef-building communities, while tropic structure of the community is a main factor to maintain development of the communities. The combined effect of biologic structure, physical structure and tropic structure leads to ecosystem balance of the reef-building communities. The whole reef-building process is closely related to occurrence and development of the metazoan reef-building communities. The overall natures and ecosystem of the community are decided by the key species in the community. The character, composition and function of the communities would change correspondingly, if the key species were taken out.