Abstract: Taken the unweathered coal gangues obtained from the Jurassic coalbed of Bulianta mine and the Car-boniferous-Permian coalbed of Baode mine located in Shendong mining area as the research subjects, the dissolution characteristics of organic matter in two kinds of coal gangues were studied comparatively through soaking experiments, and combined with three-dimensional fluorescence spectrometry and parallel factor analysis. It is significant for the underground reservoir to study mechanism of water treatment in coal mining areas. These results indicate that the total ion concentration in DOM sample of coal gangue of Bulianta mine is higher than that of Baode mine due to the different mineral constituents, and the two kind of DOM samples of coal gangue are all weakly alkaline. Among them, the DOM of Bulianta mine contains more conjugated double bonds or benzene ring simple aromatic compounds, more fulvic acid and the terrestrial humus with larger molecular weight, and the content of DOM is generally higher than that of Baode mine. But the fulvic acid and tyrosine organic matter content in Baode mine coal gangue are relatively high. According to the calculation results of FI, BIX and HIX indices of DOM samples, the DOM in two kinds of coal gangues is mainly endogenous organic matter, and it has strong spontaneous source characteristics. The earlier the geological time of coal gangue formation is, the more obvious the "microorganism source" feature of coal gangue of DOM samples are.