Community structure of macrobenthos and some physical factors (grain size, organic content, sulfide content and water quality) were studied in 5 beaches around Sichang island namely Ta Wang, Sai Kaew, Ta Yaitim, Ta Lang and Tam Pang, during October 2007 to September 2008. Macrobenthos samples in each beache were sampled along the transect lines and collected from the 0.25 m2 quadrate. This study found 114 species in 7 phylums. Ta Wang, Sai Kaew and Ta Lang beaches were dominated by gastropods (110 - 249 individuals/m2), especially of the family Cerithiidae and Potamididae. Crastaceans (Isopod) were dominated in Ta Yaitim beach (33.1 ± 15.9 individuals/m2), while bivalves (Donacidae) and crustaceans (Isopod) were more abundant in Tam Pang beach. Species composition and abundance of macrobenthos were varied in each beach depended on grain size and organic content of the sand. Positive correlations were found among organic content and the density of bivalve, gastropod and polychete, while the mean grain size showed negative correlation with polychete density. No significant relationship were found between benthos density and sulfide content in this study.