Exploring the contribution of fluorescence characteristics of dissolved organic matter (DOM) in aggregates to soil organic carbon (SOC) mineralization. Based on a 22-year organic fertilizer positioning experiment on black soil, set no fertilization (CK); chemical fertilizer (CF); low amount of organic fertilizer (OM1) added to chemical fertilizer; moderate amount of organic fertilizer (OM2) added to chemical fertilizer; and high amount of organic fertilizer (OM3) added to chemical fertilizer. The composition of soil water-stable aggregates was determined using the wet sieving method, and the spectral characteristics of DOM in the aggregates were investigated using three-dimensional fluorescence spectroscopy coupled with parallel factor (EEM-PARAFAC) technology. At the same time, the mineralization ability of the bulk soil was quantified. Comprehensively revealing how long-term fertilization affects the mineralization of SOC in the whole soil by changing the fluorescence characteristics of aggregate DOM. The results showed that compared with CK, the proportion of particle size aggregates >0.25 mm under the combination of organic fertilizer and chemical fertilizer significantly increased by 4.3%~11.9%. In comparison, the proportion of aggregates with a particle size of <0.053 mm was almost unaffected. EEM-PARAFAC found that combining chemical fertilizers and organic fertilizers can enhance the fluorescence intensity of fulvic-like, protein-like, and humic-like components in various particle-size aggregates of DOM. Among them, humic-like and protein-like components showed the strongest response to organic fertilizers in aggregates of >0.25 mm and <0.25 mm DOM, respectively. Moreover, compared to CK (BIX<0.8), the autotrophic characteristics of DOM in different particle size aggregates were significantly enhanced (BIX>1.0) after the application of chemical fertilizers and organic fertilizers. Still, the fluorescence index (FI) and humification index (HIX) changes were insignificant. In addition, the mineralization ability of SOC increases with the application of organic fertilizers, following the OM3>OM2>OM1>CF>CK pattern. At the end of cultivation (28 d), there was an increase of 68.2%~135.8%. The Mantel test and structural equation (SEM) model indicated that the fluorescence structure changes of aggregates DOM with different particle sizes had an impact on the mineralization of SOC, with the change in BIX value being the main inducing factor, and the protein-like components in DOM mainly controlled the strength of BIX. Furthermore, fertilization mainly drove the mineralization of SOC by improving the particle size distribution of >0.25 mm aggregates. In comparison, <0.25 mm aggregates mainly affected the mineralization of SOC by changing the fluorescence structure of DOM. The research results indicated that the particle size distribution of aggregates and the fluorescence characteristics of DOM, especially the BIX index, can be used to infer the mineralization ability of SOC. This can provide a scientific basis for evaluating and predicting carbon emissions from black soil after long-term application of organic fertilizers.