Fluorescence spectroscopy, UV spectroscopy, and multiple UV parameters were applied to determine and analyze the dissolved organic matter (DOM) in water of Taihu Lake, in order to find out the sources and influencing factors of DOM in water from typical areas of Taihu Lake. The results showed that the components of DOM in water from different lake areas displayed some regional characteristics. The contents of macro-molecules matters with complex structures and humic substances in water from sampling points T1 (locates in the inflow river) and T2 (represents Zhu Shan Bay Lake) were in majority. This indicated that these areas were subjected to multiple sources, including biological sources, land-based sources, and domestic sewage. In the meanwhile, the complexities of DOM from sampling points T3 (Meiliang Bay Lake), T4 (Gonghu Bay Lake), and T5 (center of Taihu Lake) were relatively low. And protein-like materials with simple structures were in majority in water from sampling point T6 (East Taihu Lake), which suggested that this area was less influenced by the external environment.