Abstract: To better understand the effects of biological and environmental factors of late Carboniferous reefs on organic reef development， through the reef community ecology and environment， comparative study was done with the late Carboniferous ecological characteristics of reefbuilding communities， effect of the biological factors on reef community development， the reef development background and construction scale in Guizhou and Guangxi. The key species occupied obvious dominance， reefbuilders grew rapidly and had a strong colonial ability， and the largescale reefs， made reefs develop more maturely in Houchang， Guizhou. While in Langping， Guangxi， no obvious key and dominant species appeared， reefbuilders were not prominent in their ecological features and poor reefbuilding ability， the environmental influence of shoal was significant and smallscale reefs were the direct causes of poor development of reefs.

Key words: late Carboniferous, reef, community, ecosystem, comparison