1�� College of Resources and Civil Engineering��Northeastern University��Shenyang 110004��China; 2�� School of Environmental and Chemical Engineering��Shenyang Ligong University��Shenyang 110159��China; 3�� College of Biological Science of Biotechnology��Beijing Forestry University��Beijing 100083��China

Abundant brachiopod fauna distributed widely in Pennsylvanian reefs of Xiaoyao Formation in southern Guizhou��China��in which were rich Choristites and Martinia fossils��The main attention in this paper is to the ecological relationship among brachiopod fauna and reef-building organisms: phylloid algae and Fomitchevella coral�� In phylloid algae reef��small brachiopod was sometimes discovered floatting on the algae leaf�� But it was difficult to find brachiopod in closely spaced phylloid algae��which was due to that perhaps brachiopod couldn't find adequate food when water flow became weak correlated with the prevention of phylloid algae��instead��the brachiopod increased in shape and quantity in sparse phylloid algae�� In large-sized coral reef��there was almost no competition for food between brachiopod and Fomitchevella�� The brachiopod shells provided biogenic hard substrate for attaching of Fomitchevella larvae and developed large reefs�� Brachiopods were precluded from substrate by Fomitchevella because of the limitation of ecological space��