348 sediment samples were taken from the Pearl River estuary to analyze their major element contents, and to study geochemical characteristics and geological significance. The results show that the main chemical compositions in surface sediments are SiO₂ and Al₂O₃, with average contents up to 60.1% and 15.1% respectively. The content of SiO₂ increases from estuary to sea, while the content of Al₂O₃ decreases. Correlation analysis and factor analysis show that SiO₂, Al₂O₃, P₂O₅, K₂O, TiO₂, MnO, Fe₂O₃ and CaO are the most important factors in surface sediments. The elements originated from marine include Na₂O and MgO, and K₂O is derived from continent and marine.