Characteristics of phosphorus fractions in surface sediments of the Lake Yangzonghai were studied applying the method of continuous extraction and classification. The element composition of C, N, H and O, UV-vis spectrum features of hydrophobic and hydrophilic dissolved organic matter (DOM), and their effects on P fractions in sediments were also clarified.The results indicated that the mobile-P contents in sediment ranged in 68.67-124.70 mg/kg and accounted for 9.81% of total phosphorus on average. The immobile-P contents in sediment ranged in 496.73-908.28 mg/kg, accounting for 60.86% of total phosphorus on average. The contents of different P forms decreased from north to south part, and the immobile-P content was significantly higher than that of mobile-P, indicating P retention in sediments. The contents of C, N and UV-vis spectrum integral area (A_240-400) of hydrophilic DOM showed a decreasing trend from north to south of the lake, while the ratios of H/C, O/C, (O+N)/C and the A_240-400 value of hydrophobic DOM presented a reversing trend. Significantly positive correlations were found between NH₄Cl-P and C, N and H contents, and the negative correlations were found between NH₄Cl-P contents and H/C, O/C, (N+O)/C, UV-vis spectrum eigenratio (E₂/E₃) of hydrophilic DOM. In addition, NaOH-rP and BD-P+NaOH-rP have negative correlations with the O and O/H ratios, but all of the NaOH-rP, BD-P+NaOH-rP and HCl-P contents in sediments have positive correlations with the A_240-400 value of hydrophobic DOM. Therefore, element composition and functional groups structure of nature organic matter is the important factors influencing the P fractions.