4 investigations were carried out on macrobenthos in Qinshan Island sea area from 2015 to 2016, and the dominant species and diversity of macrobenthos were evaluated using dominance index and diversity index. The results showed that 69 species of macrobenthos in 7 phyla were collected and identified in four seasons, including 25 species of annelids, 19 species of mollusks, 16 species of arthropods, 3 species of echinoderms, and 2 species of chordates, nemertea and coelenterates each. There were 14 dominant species. The number of species and mean density of macrobenthos in descending order were in spring, autumn, summer, winter, and the mean biomass in descending order was in summer, winter, spring, autumn. There was no obvious rule in the spatial distribution of density and biomass. The results of diversity evaluation showed that macrobenthos community was slightly disturbed and the benthic environment was slightly polluted. In addition to human interference and environmental factors, interspecific relationships and life history characteristics were also the important factors affecting the changes in macrobenthos community structure. |