Abstract: Inductively coupled plasma mass spectrometer (ICP-MS) was used to analyze the concentrations of As, Cd, Cr, Cu, Ni, Pb and Zn in the main blade, lateral blade, receptacles and pneumathode of Sargassum fusiforme at maturity, to reveal the distributions of trace elements in different tissues of Sargassum fusiforme. Our results showed that Sargassum fusiforme had a strong ability to enrich trace elements, which varied in different tissues. The trace elements usually accumulated more in receptacles and pneumathode. The distribution patterns of As, Cd, Cr and Cu in different tissues were similar, while that of Ni, Pb and Zn differed and varied with site investigated. The enrichment coefficient of As in alga was the highest, while that of Cr was the lowest. According to the results of risk assessment, there is no health risk to human body when taking Sargassum fusiforme as food except receptacles from two sites. Comparatively, the health risk of consuming branches is much lower.