River sediment from two inflow watersheds (Hongze and Tiaoxi) to Hongze and Taihu Lake in Eastern China was analyzed by the sequential extraction procedure. This study aimed to explore a spatial distribution of phosphorus fractions in river sediments and analysed the relationship between different phosphorus fractions and their environmental influence on the sediments within different watersheds in Eastern China. Five fractions of sedimentary phosphorus, including freely sorbed phosphorus, were all analyzed (NH₄Cl-P), redox-sensitive phosphorus (BD-P), bound phosphorus metal oxide (NaOH-P), bound phosphorus calcium (HCl-P) and residual phosphorus (Res-P). The order of rank of the P fractions for the river Anhe was HCl-P>NaOH-P>BD-P>NH₄Cl-P; whereas that of the Suihe river was HCl-P>BD-P>NaOH-P>NH₄Cl-P. For the rank order of the Hongze watershed, HCl-P was higher while the NH₄Cl-P contents were significantly lower. The rank order for the Dongtiaoxi river was NaOH-P > HCl-P> BD-P> NH₄Cl-P and that of Xitiaoxi river was NaOH-P> BD-P> HCl-P> NH₄Cl-P. Compared with phosphorus forms of Tiaoxi watershed, NaOH-P contents were significantly higher in the converse of HCl-P contents were significantly higher in Hongze watershed while both in NH₄Cl-P contents were significantly lower. Variations may be attributed to differential discharge of P watershed form due to land-use changes and urban river ambient conditions.