Abstract: The contents of heavy metals (Fe, Zn, Mn, Cu, As, Cr, Cd and Hg) in 13 marine macroalgae from the Nanji Islands (121°01'~121°08'E, 27°25'~27°30'N) in May 2010 and April 2011 were determined by atomic absorption spectroscopy and atomic fluorescence spectroscopy. Furthermore, the investigation on accumulating characteristics of heavy metals in macroalgae was employed by cluster analysis and principal component analysis (PCA). The results demonstrated that the heavy metal contents were significantly different within various species; meanwhile, the different distribution of each heavy metal was also presented in the same macroalgae. The average contents of heavy metals in macroalgae follows the order:Fe > Zn > Mn > As > Cu > Cr > Cd > Hg. Especially, the highest enrichment ability to Fe and Cu could be observed in Chlorophyta, while the highest enrichment ability to Mn and Zn was exhibited in Rhodophyta, but the highest content of As was found in Phaeophyta. The highest accumulation coefficients were observed in Ulva lactuca for Fe and Enteromorpha linza for Cu, which were 200553 and 12992, respectively. G.divaricatum Martens exhibited the highest accumulation coefficients for Zn, Mn, Cr and Cd, which were up to 46357, 31921, 25192 and 27556, respectively. The highest content was found in Sargassum thunbergii for As enrichment with accumulation coefficient at 65278, while the accumulation coefficient of Sargassum horneri for Hg was highest with 3165. However, the least accumulation coefficient was Corallina officinalis for Hg at only 515. Overall, the order of heavy metal bioaccumulation degree is G.divaricatum Martens > Sargassum thunbergii > Ulva lactuca > Scytosiphon lomentarius > Enteromorpha linza > Gloiopeltis furcata > Grateloupia filicina > Chondria crassicaulis > Corallina officinali > Sargassum horneri > Endarachne binghamiae > Ishige okamurae > Sargassum fusiforme.