Abstract: In order to gain a deeper understanding of the potential impact of endogenous phosphorus load on water environment of Lake Bosten, the basic physicochemical properties and the total phosphorus (TP) content in the sediments were investigated, and the fractions of phosphorus in sediments as well as the dynamic changes of phosphorus at the sediment-water interface were analyzed by chemical extraction method, thin film diffusion gradient technique (DGT), and high resolution dialysis technique (Peeper). The results showed that: (1) TP content in the surface sediments of Lake Bosten ranged from 264.26 to 719.23 mg/kg, and it was significantly higher at Kaidu River estuary (KRI) than that at the main lake area (MLR) and Huangshui River estuary (HRI) (P<0.05); calcium-bound inorganic phosphorus (Ca-Pi) had the highest proportion in TP content. (2) Similar to TP distribution, there was a higher average concentration of available phosphorus (C_DGT-P) at the sediment-water interface at KRI (0.043 mg/L) than at MLR (0.025 mg/L) and HRI (0.021 mg/L), and the phosphorus resupply coefficient of the sediments at the former location was higher. (3) Among the parameters characterizing the phosphorus release capacity, the C_DGT-P and phosphorus diffusion flux (P-Flux) at the sediment-water interface, as determined by DGT technology, were both in the order of KRI>MLR>HRI, and this characteristic was significantly regulated by weakly adsorbed inorganic phosphorus (WA-Pi), iron/aluminum-bound inorganic phosphorus (Fe/Al-Pi), and the proportion of fine particles.