Macrozoobenthic community was investigated seasonally at 12 sampling stations in Lake Nanyi of Anhui,from July 2002 to July 2004 for providing academic data for rational utilization of aquatic resources and ecological strategy for fishery resources.A total of 39 species were obtained.The highest biomass and density were presented in the winter of 2003 and the lowest density in the summer of 2004.Mollusca was by far the most dominant group,its dominant species were Corbicula fluminea,Bellamya purificata,B.aeruginosa and Alocinma longicornis.The annual average value of Shannon-Wiener diversity index,Margalef diversity index and Pielou index were 0.83,0.51 and 0.77 respectively.The results showed that the species number,biodiversity,standing stock of macrozoobenthos community were much higher in the west area than in the east area of the lake.After the construction of a reservoir,the ecological characteristics of macrozoobenthos in the lake changes very much,which results in the significant drop of the standing stock of the macrozoobenthos.