Four season investigations on macrofauna were carried out from August 2002 to May 2003 in Yueqing Bay where 18 sampling stations including 14 stations in non-farming area, 2 stations in oyster-farming area and 2 stations in fish-farming were set. 124 species were identified, including 41 species of polycheata, 37 species of mollusc, 22 species of crustacea, 10 species of echinoderm and 14 of others. There were 5 dominant species which were Nassarius siquinjorensis, Virgularia gustaviana, Sternaspis scutata, Capitella capitata, and Protankyra bidentata. The average biomass was 41.95 g m^-2 and the average density was 85 ind m^-2. Echinoderm occupied the highest proportion in total biomass (about 60%) and mollusc occupied the highest proportion in total density (about 35%). The spatial and temporal distribution of biomass and density was asymmetric in Yueqing Bay. Biomass and density in bay-head area and culture area were higher than other areas in the Bay, and in spring were higher than in other seasons. The characteristics on macrofauna community were different from diverse culture mode and different season. Data of species, quantity, diversity, K-dominant curve were analyzed and resulted in: (1) In fish-farming area, macrofauna community was influenced by organic pollution, especially it was seriously disturbed in summer and autumn. (2) In oyster-farming area, macrofauna was active and excited by lesser oyster metabolic products and it was restricted by more oyster metabolic products, but it was not yet destroyed in the area. In comparison of macrofauna status with history data of the bay and the adjacent bays, its biomass and density were obviously higher than that 20 years ago, which were resulted from the increase of its feed, the particulate organic matter, input from both domestic, industrial and agricultural waste waters and the sunk of aquiculture waste feed and metabolic products, particularly in recent years the water exchanges between inside and outside the bay have been becoming weak, due to the increase in aquaculture. Although macrofauna status in fish-farming area in Yueqing Bay is batter than in Xiangshan Bay because of shorter aquiculture time and more reasonable aquiculture arrangement, problems of environment pollution and ecological disturbance deserve great attention.