Abstract: A four-cruise investigation was conducted on the macrobenthos at 20 sampling locations in Laizhou Bay in 2011, and the method based on functional group was adopted to study the functional groups and diversity of the macrobenthos. A total of 177 macrobenthic species were recorded, of which, polychaete, mollusk, and arthropod were dominant. The percentage of the species number in different functional groups to the total species ranked in the order of C>D>Pl>O>Ph, the percentage of the inhabited density showed the sequence of Pl>D>C>O>Ph, and the percentage of the biomass was Pl>C>D>O>Ph. The cluster analysis showed that there were three macrobenthos assemblages in the Bay. No significant differences were observed in the species number, inhabited density, and biomass  between seasons. The Marglef index (d) ranked in the order of C>D>Pl>O, and showed a significant difference between seasons (P<0.05). The Pielou’s index (J′) ranked in the order of C>D>O>Pl, and the Shannon  index (H′) was C>D>Pl>O, but no significant differences were observed between seasons.  There was a significant positive linear correlation between species diversity and functional group diversity. The ABC curve showed that the macrobenthic community was disturbed in different degrees. There were four trophic levels in the macrobenthic community and their food source, and the macrobenthic functional groups belonged to the Ⅱ, Ⅲ, and Ⅳ trophic levels. A complicated food web was composed between all the trophic levels.