The concentrations and distribution of dissolved total phosphorus(DTP) and dissolved inorganic phosphorus(DIP) in the sediment interstitial water from Lake Poyang were determined based on the sampling in January 2010.The results showed that the average DTP and DIP concentrations in the overlying interstitial water of Lake Poyang (0-2 cm) were 0.134 mg/L and 0.082 mg/L, respectively, which showed no significant spatial variation between sampling sites.The profiles of DTP and DIP con-tents in the core sediment interstitial water increased with depth at 0-18 cm and then decreased with depth at 18-28 cm.For the DIP, no significant correlation was found between interstitial water and sediment.But for the DTP, a certain correlation existed be-tween the surface interstitial water and sediment, indicating that the concentration of TP in the surface sediment can influence the DTP content in the interstitial water.