【Objective】Soil dissolved organic matter (DOM) plays an important role in the biogeochemical processes in wetland ecosystems. This study aimed to uncover the total quantity, components, and source features of DOM in the river-lake confluence area of Hongze Lake. 【Method】The spectral characteristics of DOM in soil covered by lake-sedge, reed, poplar, and willow in the river-lake confluence area of Hongze Lake were studied using UV-visible absorption spectroscopy and the three-dimensional fluorescence spectroscopy method. 【Result】The results showed that the DOM content of soil covered by different vegetation was in the order of reed wetlands, lake-sedge wetlands, poplar forests, and willow forests. Additionally, soil within 40 cm of reed wetlands contained a dissolved organic carbon level of 193.2 mg·kg–1. The soil DOM values of A250/A365, SUVA254, SUVA260, and SR ranged from 3.7 to 4.5, 1.3 to 1.8, 0.86 to 1.8, and 3.6 to 4.9, respectively. Moreover, the molecular weight, aromaticity, and hydrophobicity of lake-sedge wetlands soil were significantly higher than those of other soils. As revealed, DOM's molecular weight, aromaticity, and hydrophobicity decreased in the 20~40 cm soil layer as opposed to the 0~20 cm soil layer. As shown by EEM-PARAFAC, four fluorescence components, terrestrial humic acid-like, marine humic acid-like, fulvic acid-like, and protein-like, have been recognized. Humic acid-like substances were found in all soil layers, with 55.1% to 70.1% being the majority, but the 20~40 cm soil layer saw a rise in protein-like substances, especially in reed wetlands soil. The FI, BIX, and HIX indices of DOM varied depending on the vegetation, with a range of 1.3 to 1.5, 0.47 to 0.72, and 1.7 to 7.4, respectively. The soil DOM properties were greatly influenced by the coverage of different vegetation. Also, terrestrial humic acid-like substances were the dominant soil DOM in the river-lake confluence area of Hongze Lake, with a lesser level of self-obtained and a higher degree of humification. 【Conclusion】In summary, the research results revealed the differences in total DOM content and spectral characteristics of soils with different vegetation cover in the river-lake confluence area of Hongze Lake. It further provides a scientific basis for understanding DOM environmental behavior in the river-lake confluence area, thus, strengthening carbon sequestration efficiency in key areas and enhancing habitat protection.