Sediment-Water-V.natans in a simulated lake system was built to study phosphorus concentrations in sediment, water and V.natans during the growth period of Vallisneria natans.Simulation results indicated that different phosphorus concentrations in sediment were reduced significantly during the growth period of V.natans.Total phosphorus (TP), NaOH extracted phosphorus (NaOH-P), HCl extracted phosphorus (HCl-P), inorganic phosphorus (IP) and organic phosphorus (OP) were decreased by 65.71, 39.06, 11.65, 52.86 and 11.28 mg/kg, respectively.The IP absorption efficiency of V.natans was higher than that of OP, and the NaOH-P absorption efficiency was higher than that of HCl-P.The concentration of TP in water was decreased to 0.04 mg/L.Redox potential (Eh) was increased significantly but pH was decreased in sediment.There were significantly positive correlations among TP, NaOH-P, HCl-P, IP and OP.Different phosphorus fractions were negatively correlated with Eh at different levels, significantly positive-correlated with pH, and significantly negative-correlated with V.natans root area.Phosphorus ab-sorbed by V.natans was 292.24 mg at the end of the experiment.The phosphorus in sediment, V.natans and water were 92.04%, 7.85% and 0.12%, respectively.The result indicated that V.natans affected the concentrations of phosphorus in sediment through increasing redox potential and decreasing pH.V.natans reduced phosphorus release risk through uptaking phosphorus from water and sediment.The rank from high to low order of phosphorus absorption ratio by V.natans was NaOH-P, HCl-P, IP, and OP.