Based on the monitoring data of six representative lakes in Saihanba, this study analyzed the spatial distribution, sources and ecological risks of eight metal ions, followed by exploring the impacts of DOM and its spectral parameters on the distribution of heavy metals. The results show that the average contents of Cr, Fe, Co, As, Cu, Zn, Cd and Pb were 0.09, 82.89, 0.04, 0.88, 0.83, 8.70, 0.03 and 0.41 μg/L, respectively, which were all lower than Class III of the Environmental Quality Standard for Surface Water. The 8 heavy metals displayed high homology, suggesting the natural sources, with certain interference from the interference of human activities. To further investigate the relationship between DOM and heavy metals, three fluorescent components (C1, C2, C3) and spectral parameters of DOM were identified by excitation-emission matrix-parallel factor analysis (EEM‑PARAFAC). DOM can influence the spatial evolution of heavy metals. As, Cd and Cu were positively correlated with DOC. As was positively related to C3 components, Cd and Pb were positively correlated with BIX. Spatially, Taiyang Lake (TYH) showed high DOM content and BIX value, which significantly promoted the enrichment of Cu, As, Cd and Pb. The evaluation results of single factor and Nemero comprehensive pollution index show that the heavy metal pollution level in Saihanba is low, and the risks mainly come from Fe and As. Attention should be paid to the interactions between heavy metals and DOM, along with the potential ecological risks.