The investigation of zoobenthos was conducted in 48 reservoirs of Jiangsu Province from May 1998 to Jan.1999.A total of 75 taxa of zoobenthos were recorded, of which Branchiu-ra, Limnodrilus, Aulodrilus, Pelopia, Cryptochironomus were dominant.The density and biomass of zoobenthos were 288.4 ind./m² (43.2-928.2)ind./m² and 8.753 g/m² (0.235-61.884 g/m²) respectively.The density of zoobenthos in southern reservoirs was higher than that of central and northern reservoirs, while the biomass of zoobenthos in northern reservoirs was greater than that of central and southern reservoirs.The seasonal change of standing crops of different groups of zoobenthos were significant.The Goodnight biotic index of zoobenthos as indicator of water quality show that there was no pollution in most reservoirs.It was calculated that the potential fishery production capacity from zoobenthos was 5.8kg/hm².