This study was conducted at the long-term positioning experimental field of the Hainan Danzhou Tropical Agro-ecosystem Nation Observation and Research Station, China. Three treatments, including no fertilization (CK), inorganic fertilization (NPK), and combined inorganic-organic fertilization (NPKOM), were selected to investigate the impacts of different fertilization patterns on DOM concentration and spectral characteristics in the latosol profile using multiple spectral techniques (ultraviolet-visible spectroscopy, and three-dimensional fluorescence spectroscopy) and parallel factor analysis (PARAFAC). The results showed that compared with CK, DOM contents were reduced under NPK and NPKOM, and DOM contents in the surface layer (0-20 cm) were significantly higher than those in other layers (20-100 cm). PARAFAC analysis results suggested that DOM was mainly composed of three fluorescent components: terrestrial humic-like substances (Ex/Em=355 nm/428 nm, C1), natural fulvic acid (Ex/Em=420 nm/471 nm, C2), and protein-like substances (Ex/Em=310 nm/346 nm, C3). NPK and NPKOM significantly increased the relative abundances of C1 and C2 components but decreased that of C3 component. With the increase of soil depth, the relative abundances of C1 and C2 components decreased, whereas that of C3 component increased. In conclusion, due to fertilization increasing the accumulation of crop residues and the release of root exudates, coupled with the release of DOM from organic fertilizer itself, the humification degree of DOM under NPK and NPKOM increased while the autochtonous source characteristics decreased in contrast with CK. Furthermore, the aromaticity and hydrophobicity of DOM in the cultivated soil layer (0-40 cm) under NPK and NPKOM were significantly lower than those under CK.