Abstract: OBJECTIVE To establish a method for the determination of 20 heavy metals and trace elements in Sargassum pallidum and Sargassum fusiforme and its adulterants by inductively coupled plasma mass spectrometry(ICP-MS), and to determine the distribution of heavy metals and trace elements in Sargassum pallidum and Sargassum fusiforme. METHODS The 3.0 mL nitric acid and 1.0 mL ultrapure water were added into the sample and digested to the microwave digestion procedure and then determined by ICP-MS. The carrier gas was argon, the collision gas was helium, the plasma gas flow rate was 15.0 L·min^-1, the carrier gas flow rate was 1.17 L·min^-1, the plasma radio frequency power was 1.3 kw, and the creep pump rotation number was 30 r·min^-1. Full quantitative analysis model was adopted. RESULTS The 20 heavy metals and trace elements measured had a good linear relationship. The detection limit for each element was of 0.001-1.701 μg·L^-1, with the average recovery from 78.6% to 108.2%. As was the highest content of harmful element, Mg, Ca, Fe, Zn, Sr were higher than other elements. CONCLUSION The method is simple, accurate, specialized, repeatable and sensitive, internal standard method can improve the accuracy of measurement results and can be used for the determination of heavy metals and trace elements in Sargassum pallidum and Sargassum fusiforme and its adulterants.