After the investigation and analysis of benthons of Hengqin Island sea area in May 2008,33 species were found, including comate,mollusk,crustacean and Echinodermata.Comate was the dominant species,with a ratio of 42.42% of all the species.Paraprionospio pinnata,Heteromastus filiformis and Magelona crenulifrons were dominated.The total inhabitation density of benthons was 236.3 ind·m^-2,and comate was the dominant species,with a ratio of 71.94% of the total inhabitation density.Besides,the total biomass of benthons was 53.0 g·m^-2,and mollusk was the dominant species,with a ratio of 43.58% of the total biomass.The average diversity index and evenness of benthons were 2.62 and 0.83,respectively.Biodiversity indices showed that the area was at a lightly-moderate polluted status.Our results show a relatively higher quantity in biomass, inhabitation density,and diversity index and evenness in Hengqin Island sea area,as compared with other data from researches in the Pearl River Estuary.