Against the backdrop of rapid industrialization and urbanization, the contamination of the aquatic environment by heavy metals (HMs), particularly lead (Pb), cadmium (Cd), and zinc (Zn), is becoming an increasing concern. The interaction between dissolved organic matter (DOM) and these metals significantly influences the mobility and bioavailability of HMs in aquatic ecosystems. Although the role of DOM in the cycling of HMs is crucial, the relationship between the properties of DOM and its binding capacity for these target HMs remains poorly understood. In this study, we utilized the fluorescence quenching titration (FQT) method to determine the conditional stability constants (log KM) of sediment-extracted DOM (SeDOM)-HM complexes with sediment of different origins, focusing on Pb, Cd,and Zn. Additionally, we employed the equilibrium dialysis ligand exchange (EDLE) technique to compare the properties of DOM with the direct adsorption (%) of SeDOM-HM across a range of dissolved organic carbon (DOC) concentrations. The results revealed a wide range of binding strengths (logKM=3.12–5.41) between SeDOM and the target HMs, confirming that the percentage of DOM-bound HMs increased with increasing DOC concentration. In particular, the presence of chromophores, such as aromatic compounds, and variations in molecular weight and carbon structure within SeDOM, were identified as the main factors determining the affinity for metals. This study highlights that the high affinity of terrestrial-derived, humified DOM for these HMs poses a potential environmental risk as a carrier of HMs