Four lakes with different pollution state (mesotrophic, meso-eutrophic and eutrophic) were studied and compared over a period of one year for the community structure and biodiversity of zoobenthos. Considerable differences in zoobenthos species compositon, dominant species, abundance, biomass and diversity index were observed. The results showed the higher pollution state of lake, the smaller species number, biodiversity based on Margalef index and Shannon-Wiener index. Inversely, zoobenthos density increased with the aggravation of lake pollution on the whole. Ecological characteristics of environmental indicators were also discussed. The density of the oligochaete Tanypus chinensis was positively correlated with the state of lake pollution. A negative correlation was apparent between the number of species, density and the pollution level. These results indicated that a clear decrease in biodiversity should be attributed to water pollution.