Fluorescence spectroscopy and UV-visible absorption spectroscopy were applied and multiple related parameters were analyzed to study both horizontal and vertical distributions of dissolved organic matters (DOM) in the sediment of the Taihu Lake, to explore their spectral characteristics, possible sources, influencing factors, and environmental implications. And the results showed that ... [Show full abstract] compositions of sediment DOM varied between different lake areas and between different depths. Horizontally, sediment DOM in the Zhushan Bay contained more complex macromolecule substances and humus. This lake area is impacted by multiple DOM sources such as land-based sources and biological sources. In contrast, sediment DOM in the east part of the lake was less complex, and dominated by protein-like substances, indicating that this part is less impacted by land-based input than in the Zhushan Bay. Vertically, DOM compositions of the Zhushan Bay sediment exhibited a declining complexity with the depth, and DOM of the river sediment presented a similar trend, which implies that the degradation of DOM is more sufficient at the deeper sediment. Comparing the spectra of sediment DOM at the same depth, it was found that DOM composition of river sediments was more complex than that of lake sediments, which indicates that the DOM of river sediments was less degraded than that of lake sediment at the same depth, and was impacted by multiple sources.