To elucidate the effect of synergistic fertilizers amendment on the flurorescence characteristics and humification degree of fulvic acid in soil, field trials were conducted in Nenjiang county and Aihui district of Heihe city, respectively. Totally, there were five treatments: (1) balanced fertilization (NE); (2) 25% reduction in balanced fertilization (CK), (3) 25% reduction in balanced fertilization combined with nano-carbon synergist (T1), (4) 25% reduction in balanced fertilization combined with zeolite synergist (T2); (5) 25% reduction in balanced fertilization combined with biochar synergist (T3). Three-dimensional fluorescence region interal (FRI) method was used to determine the change of relative Fmax content among treatments. The application of synergistic fertilizers greatly improved the soil humification degree and exhibited the following pattern: T2>T1>T3>NE>CK. T2 treatment showed the highest soil humification degree and nutrient-supply capability. Especially, the ratio of relative content of the visible fluorescent FA region Ⅴ and ultraviolet fluorescent FA region Ⅲ (PⅤ, ｎ/PⅢ, ｎ) in T2 treatment was improved by 5.81% in Nenjiang county, and was improved by 4.65% in Aihui District as compared with CK. Soil FA was divided into C1 and C2 component using the parallel factor analysis. The Fmax ratio of C2 to C1 component in T2 treatment was improved by 22.09% in Nenjiang County, while was improved by 20.93% in Aihui District as compared with CK. The C2 component exhibited more complex structure and higher condensation than C1 component. The application of synergistic fertilizers improved the proportion of C2 component in FA and exhibited the following pattern: NE＞T2＞T1＞T3＞CK, indicating enhanced soil nutrient-supply capabilities by synergistic fertilizers. Overall, this study indicated that the T2 treatment significantly enhanced soil humification degree as compared with CK, and its positive effect on soil FA was superior to nano-carbon and biochar synergists. Therefore, the application of zeolite synergist would effectively improve soil nutrient-supply capability and ameliorate soil ecological conditions.