Abstract: In order to comprehensively examine the properties of dissolved organic matter (DOM) beneath typical vegetation in coastal wetland at Yellow River Estuary, we collected soil samples from the root surfaces of three dominant plants (Tamarix chinensis, Phragmites australis, and Suaeda salsa) in July and September 2022, as well as February 2023. These samples were analyzed to investigate the properties of soil DOM of different vegetation during the growing and stagnant periods, and to explore their associations with environmental factors. The results revealed significant differences in the concentrations of dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) among the vegetation types, following an overall trend of T. chinensis＞P. australis＞S. salsa. There are also differences in different growth stages: during the rapid growth period, T. chinensis had the highest content, followed by P. australis and S. salsa; at the end of growth period, T. chinensis remained the highest, with S. salsa surpassing P. australis; whereas in the senescence phase, S. salsa exhibited the highest content, followed by T. chinensis and P. australis. Utilizing excitation-emission matrix spectroscopy combined with parallel factor analysis (EEMs-PARAFAC), we identified three humic-like components (C1, C2, C3) and one protein-like component (C4) in soil CDOM, with humic-like components accounting for the majority (over 86%). Comprehensive analysis using optical indices such as SUVA₂₅₄, S_R, FI, BIX, and HIX revealed that soil DOM in the study area was predominantly hydrophobic, characterized by high degrees of humification and aromaticity, primarily sourced from terrestrial inputs, with minimal autochthonous contributions.