Abstract: Distribution of major elements in marine sediments and water system was studied in this paper by using a modified sequential extraction procedure according to the methods of Tessier,BCR and so on. Concentrations of Ti,Al,Na,Mg,K,Ca,P,Fe,and Mn in the extracted components leached by different reagents were measured using inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma atomic emission spectrometry (ICP-AES). The results indicate that the most abundant elements extracted by water are Na and Ca, and Ca and P tend to be abundant in organic materials compared with other elements. Large amounts of Ca and Mg are extracted by HAc, which may result from dissolution of carbonate. Additionally, some of the Al, Mn, Na and K are also extracted by HAc. In the component extracted by diluted HCl, the concentrations of these elements except Ti are high, indicating that authigenic materials were significantly dissolved. However, nearly all the Ti in sediments retains in the residue after previous four extraction procedures, suggesting that Ti is mostly hosted in detrital component. The Ti-normalized ratios of other elements in the extracted components all show significantly higher values than those of the average composition in sediments in China, indicating that the dissolved components are mainly authigenic biogenic materials, and the residue after this sequential extraction can basically represent the terrestrial detrital component in sediments.