Abstract: In this paper, the results of research on the benthos at rocky bottom in five sections of Yuhuan National Marine Park, in August 2017, have been reported.A total of 113 species including 38 spceies of Mollusca, 25 species of Crustacea, 25 species of Polychaeta, 11 species of Plantae, 7 species of Cnidaria, and 7 other species were identified.The dominant species were Tetraclita japonica, Septifer virgatus, Tetraclita squamosa squamosa, Exosphaeroma oregonensis, Hyale honoluluensis, Spirobranchus kraussii and Kellia porculus.The average abundance and biomass for all the sections were 3772 ind/m² and 2853.32 g/m², respectively.Other calculated parameters are showed as follows:Shannon-Wiener(H')=1.89, Margalef index(d)=1.30, Pielou index (J)=0.48.Compared with the macrobenthos in other sea islands which are adjacent to the rocky intertidal zone, the macrobenthos in the Yuhuan National Marine Park had a high level of biodiversity and biomass a moderate habitat density.