In this paper, we apply excitation-emission matrix spectroscopy (EEMs) and parallel factor analysis (PARAFAC) to investigate the fluorescence spectral of water soluble organic matter (WSOM) in the suspended solids of Lake Wuli of Lake Taihu. We also analyze the component types and the distribution and the source of WSOM based on the obtained spectral characteristics and further study the correlation between water soluble organic/inorganic nitrogen components and WSOM components. The results show that two microbial humic-like (C1, C2), and one tryptophan-like (C3) can be identified as the principle components of WSOM. The total fluorescence intensity (Ct) is 57.56-200.01 R.U./g, with an average value of 115.42 R.U./g, with C1, C2 and C3 ratios of 35.55%, 34.05% and 30.40%, respectively. In spatial, fluorescence intensity decreases from east to west in Lake Wuli, and the intensity in the lakeside area is higher than that in the center area. Moreover, fluorescence index is between 1.48 and 2.34, and biogenic index is between 0.65 and 0.87. In conclusion, WSOM in the suspended solids of Lake Wuli mainly come from microorganisms, algae aquatic and organisms. Depending on the results of multiple regression analysis, WSOM is closely related to the migration and transformation of nitrogen in suspended solids, and the correlation coefficient between organic nitrogen and WSOM fluorescent components is greater than that between inorganic nitrogen and WSOM.