Abstract: The present study reported on the community structure characteristics of macrobenthos, based on water samples of 30 stations collected in near Zhao'an Bay in summer (August) and autumn (October) of 2015. 165 species were indentified, which indicated macrobenthos species were abundant in this area. There were 80 polychaetes, 32 molluscs and 26 crustaceans, which were the dominant taxa. Polychaeta was the dominant taxon in summer and autumn, and Paraprionospio pinnata, Ophelia acuminate, Terebellides stroemii, Nephtys oligobranchia and Amaeana trilobata were the dominant species. The average biomasses of macrobenthos were 18.22 g/m² and 8.18 g/m² in summer and autumn respectively, and the average densities were 120 ind/m² respectively and 73 ind/m² respectively.The biomass was mainly composed of polychaeta, mollusca and echinodermata. The density was mainly composed of polychaeta. Distributions of macrobenthos biomass and density showed a decreasing trend gradually from inshore to offshore. The diversity index of macrobenthos in autumn was slightly higher than that in summer, but both of them were at a medium level. Compared with the three different areas, the microbenthic species, biomass and diversity in the open bay were much higher than that in the inner bay and in the bay mouth. Compared with the historical data, the average biomass and density of the survey were significantly decreased. Biomass and density composition and dominant species had significant changes.