The potential environmental effects of fecal water are determined by the composition changes of substances. Dissolved organic matter (DOM) is an important component of fecal water. In this study, the content of DOM in pig and dairy manure slurries was analyzed by batch mesophilic anaerobic fermentation with a total solid concentration (TS) of 4% and 8%, respectively. DOM’s fluorescence spectrum characteristics and component variation characteristics in raw and digested slurries were analyzed by three-dimensional fluorescence spectroscopy (3DEEM) and parallel factor analysis (PARAFAC). After mesophilic anaerobic fermentation, there sults showed that DOM content in slurries decreased significantly (p<0.001). DOM of manure slurries mainly contained four fluorescent components: tyrosine like, fulvic acid like, tryptophan like and humic acid like. The relative content of humic acid increased significantly (p<0.05), but the relative content of fulvic acid increased only in the treatment of TS=8% but decreased in TS=4%. The humification index of DOM in digested slurries increased significantly (p<0.01), but the humification degree of DOM in pig manure slurries was significantly higher than that in dairy manure slurries. The results can provide theoretical support for evaluating potential environmental effects of livestock manure slurries utilization in farmland.