Abstract: Open-pit coal mining has a significant impact on the content and composition of dissolved organic matter (DOM) in each layer of soil profile. In this study, three-dimensional excitation-emission matrix fluorescence spectroscopy (3D-EEM) and ultraviolet-visible spectroscopy (UV-vis) were used to analyze the DOM in the soil profile (0-100 cm) of Xilinhot open-pit coal mine dump from 1-7 years, and to determine the spatiotemporal variation of DOM composition and source in the soil profile during the ecological succession of the open-pit coal mine dump. The results showed that: (1) The DOC content in the soil profile of the open-pit coal mine dump ranged from 102.70 mg/kg to 475.80 mg/kg. The proportion of protein-like compounds (29.97%-60.39%) was the highest, followed by the humic content (16.09%-44.27%). The DOM in the open-pit coal mine dump was mainly derived from microbial metabolites and had low aromaticity and humification characteristics. UV-vis analysis showed that with the increase of the number of years, the content of carbonyl, carboxyl, hydroxyl and ester in the aromatic ring of DOM increased. The proportion of humic substances first decreased and then increased, and the proportion of protein-like compounds first increased and then decreased. The proportion of fulvic acids showed a downward trend. (2) With the increase of soil depth, DOM content showed an upward trend, with its lower autogenous characteristics and lower microbial activity in soil, and obvious peaks appeared in the subsurface layer (20-40 cm). The proportion of protein-like materials in DOM fluorescence components of deep soils decreased with the increase of years. The vertical change of fulvic acids was less in open-pit coal mine dump of different years, and the proportion of humic acids increased in open-pit coal mine dump with the increase of years. As the surface vegetation grew out of nothing, the autogenous characteristics of DOM decreased and its degree of humification increased. (3) The results showed that the pH of soil profile could be used as a good indicator to evaluate the humification degree of DOM, and the total nitrogen (TN) could indicate the molecular weight of DOM. The research shows that DOM fluorescence and absorption characteristics in soil profile of open-pit coal mine dump in different years can be used to evaluate the environmental management and ecological restoration of open-pit coal mine dump.