Vegetation covers can do well in carbon sequestration and water retention. In this paper, we used artificial runoff and artificial rainfall equipment to simulate rainfall (storm: 50 mm·h-1) on a 6° slope with or without vegetation planting. In this case, combined with the 3DEEM-PARAFAC method, the source and component structure of runoff liquid (Dissolved Organic Matter, DOM) at different slope locations are analyzed to determine the relationship between DOM and the carbon and water sequestration effect of the soil. The results showed that: ① Compared with bare ground, the reduction of sediment concentration and (Dissolved Organic Carbon, DOC) of the vegetated surface is consistent: overland runoff>through runoff>subsurface runoff. Besides, the rank of the reduction of soil erosion is through runoff>subsurface runoff>overland runoff. Compared with bare ground, the rank of runoff reduction of the vegetated surface is: subsurface runoff>through runoff>overland runoff. ②According to the analysis of the fluorescence index, the results of FI and BIX characterization are the same. The source of DOM is influenced by the metabolism of the endogenous material: overland flow>through runoff>subsurface runoff. Compared with the humus source of bare land, the humus source of the vegetated surface changed from endogenous material to the combination of endogenous material and allothigene. The HIX index under vegetation covers is higher than that of bare land, and the degree of humification of runoff fluid is overland flow>through runoff>subsurface runoff. ③By parallel factor analysis, different runoff fluid DOM included four fluorescence components: humic acid-like ( C1: Ex/Em=260/455 nm), UV fulvic acid-like (C2: Ex/Em=240/395 nm), tryptophan-like (C3: Ex/Em=230~275/335 nm, 230~275nm/400 nm) and tyrosine-like (C4: Ex/Em=215/395 nm). ④The analysis of fluorescence intensity and Fmax values of different treatments showed that the Fmax values of the treatment with vegetation cover were all greater than those of the bare land. The Fmax values of C1, C2 and C4 components showed the same trend: above-ground runoff>soil flow> underground runoff. The Fmax values of C3 components showed the trend: above-ground runoffin-soil flow>subsurface runoff. ⑤ Runoff, erosion, and sediment concentration are positively correlated, while C1 and C4 components are significantly negatively correlated with runoff and erosion. Based on this, according to DOM fluorescence spectrum characteristics of slope rainfall-runoff, vegetation coverage can change organic matter components in soil, which provides the theoretical basis for the healthy development of soil ecosystems in the eroded environment. Moreover,it also indicates that the stability and content of humic acid and protein-like substances play an important role in soil consolidation and water retention.