【Objective】The forestland soil carbon pool is a key support for the global carbon cycle, especially the active carbon component—dissolved organic matter (DOM). The aim of this study is to clarify the total amount, components, and properties of DOM within 1-meter depth of forestland soil, and to enhance the understanding of the formation, transport, and transformation of DOM in forestland soils. 【Method】A plantation (main tree species: Koelreuteria paniculata and Cedrus deodara) was applied as a model forestland, and the UV/visible and fluorescence spectroscopy techniques were used to investigate the vertical distribution characteristics of DOM and its components in the soil layers of 0~20 cm, 20~40 cm, 40~60 cm, 60~80 cm, and 80~100 cm. 【Result】The results showed that the organic matter content and DOM content in the 0~20 cm soil layer of the forestland were significantly higher than those in other soil layers, especially in the 80~100 cm soil layer, which can up to 4.1 times higher for TOC and 2.7 times higher for DOC. However, the DOC/TOC ratios were relatively high in the 60~80 cm and 80~100 cm soil layers. The UV spectral indices A250/A365, SUVA254, SUVA260, and SR of forestland soil DOM ranged from 4.1 to 20.3, 0.3 to 2.6, 0.3 to 2.5, and 1.4 to 8.5, respectively. The aromaticity, molecular weight, and hydrophobicity of forestland soil DOM decreased with increasing soil depth. Within the 1-meter depth, the fluorescence components of forestland soil DOM exhibited distinct vertical differentiation characteristics. Based on parallel factor analysis, five components of forestland soil DOM were identified: two humic-like substances, one fulvic-like substance, one tryptophan-like substance, and one tyrosine-like substance. With increasing soil depth, the contents and proportions of humic-like and fulvic-like substances decreased, with the lowest proportion being 23.7%; in contrast, the content and proportion of tryptophan-like substances increased, reaching up to 53.6%. The FI, BIX, and HIX indices of forestland soil DOM ranged from 1.0 to 1.6, 0.6 to 0.9, and 0.4 to 4.7, respectively, indicating that the DOM was mainly exogenous such as derived from plant and animal residues. As soil depth increased, the autochthonous characteristics of DOM gradually strengthened, while the humification degree decreased. 【Conclusion】In summary, the results revealed the exogenous characteristics of forestland soil DOM, its stepwise screening and decomposition characteristics along the vertical profile, and the significant heterogeneity of DOM content, components, and properties among different soil layers. These findings provide a data foundation and scientific basis for understanding the underground carbon behavior of forestlands, calculating the underground carbon storage of forestlands, and regulating carbon sequestration in forestlands.