Based on the investigations of bilogical resources on Dec..1999 in winter Gucheng Lake Jiangsu Province, the biomass abundance of zooplankton, hydrophyte as well as compositions and community structures are analysed.Moreover the changing tendency in 1990-1999 and the culturing capacity of fishery in Gucheng Lake are discussed.Although the water quality of Gucheng Lake belongs to Grade 3 according to national surface water quality standards for drinking water,yet the lake water is under eutrophication gradually,especially in recent years.The potential fishery yields of Gucheng Lake is estimated to be 0.8 million kilogram.Some measures must be taken to prevent the aquatic environment from further deterioration so that the biological resources be protected and utilized in a sustainable way.