Abstract: Based on an investigation in Jiushan Islands in September 2017 and September 2018, we analyzed the rocky intertidal macrobenthic composition and community structure, including community composition, abundance, biomass, dominant species, and functional traits, using the methods of clustering and ordination. The results showed that a total of 25 macrobenthic species were recorded, including 18 Mollusca species, 6 Crustacean species, and 1 Cnidaria species. The mean biomass was 1228.40 g·m^-2, and the mean abundance was 676.00 ind·m^-2. The crustacean Tetraclita squamosawas the major contributor to total biomass, accounting for 42.39%. Mytilus unguiculatus, Littorina brevicula, Mytilisepta virgata and Tetraclita squamosa were the major contributors to total abundance, accounting for 59.96%. The spatial variation of community structure was much greater than temporal variation. Biological zonation was described, including upper Littorinids zonation and lower mussel-barnacle algae zonation. Compared with other rocky intertidal zones in Zhejiang, the species richness, total abundance and total biomass in Jiushan Islands were lower. Our results can provide basic data for future ecological environment assessment of the reserve, marine biological conservation, and scientific research.

Key words: macrobenthos, intertidal zone, Jiushan Islands, dominant species, functional trait.