In order to understand the composition, source and structural characteristics of nitrogen content and dissolved organic matter (DOM) in the soil of Erhai Lake Basin, nitrogen and DOM in the surface soils of different land use types (dry land, paddy field, forest land and wetland) were studied by using ultraviolet absorption spectroscopy and three-dimensional fluorescence spectroscopy combined with parallel factor analysis (PARAFAC). The results showed that total nitrogen (TN) content in paddy field (1.93 g/kg) and NO^-₃-N content in dry land (32.47 mg/kg) were significantly higher than those in other land use types. NH⁺₄-N content in paddy field was only significantly different from that in forest land, and there was no significant difference in other land use types. Soil dissolved organic carbon content showed paddy field > wetland > forest land > dry land. The slope ratio (S_R) of UV absorption spectrum, E2/E3, SUVA₂₅₄ and SUVA₂₆₀ showed that dry land and forest land had larger molecular weight, higher aromatization level and more hydrophobic components than paddy field and wetland. The fluorescence spectrum autogenic index (BIX), fluorescence index (FI) and humification index (HIX) showed that soil DOM in the study area came from a mixed source of microbial activity and litter, and it was biased towards terrestrial input, and the overall humification degree was low. The results of PARAFAC showed that the soil in the study area was mainly composed of four fluorescent components: C1 (humic acid-like), C2 (fulvic acid-like), C3 (tryptophan-like) and C4 (Long-wavelength humic-like). The highest average contribution rate of soil DOM was 32.91% of C1 component, and the lowest was 18.13% of C4. The highest average contribution rate was from C1 component to paddy field and from C2 component to dry land, forest land and wetland. The result of correlation analysis showed that soil DOM was more affected by TN and NH⁺₄-N than NO^-₃-N, indicating that it is closely related to the migration and transformation of nitrogen.