As a typical lake strongly influenced by human activities, Lake Erhai has experienced eutrophication and anthropogenic ecological restoration, and its carbon pool characteristics and carbon cycling patterns may change accordingly. As a direct participant in the organic carbon cycling process in lakes, dissolved organic matter (DOM) of different sources have different biogeochemical processes and fates. Therefore, studying the composition and source characteristics of DOM in lakes is beneficial for better understanding the organic carbon cycling patterns during lake eutrophication and environmental remediation processes. In this study, spatial distribution in concentrations, compositions and sources of DOM from water columns in the north-central areas of Lake Erhai were investigated by methods of stable carbon isotopes, ultraviolet fluorescence spectroscopy and three-dimensional fluorescence spectroscopy. The geochemical significances of isotopic and fluorescence characteristics of DOM in Lake Erhai also were discussed. Results showed that the total dissolved organic carbon concentration in the lake was stable, with a range of 4.21-4.66 mg/L (mean (4.37±0.12) mg/L). By examining early DOM concentrations, it was found that periodic eutrophication exhibited seasonal fluctuations but long-term accumulation. Compared with other lakes on the Yunnan Plateau, the DOM concentration in Lake Erhai was at a moderate level, which recorded the intensity of lake productivity and had a certain response relationship with the degree of eutrophication. The stable carbon isotopes variation range was -26.8‰--26.2‰ (mean -26.4‰±0.2‰), and the variation ranges of absorption coefficient a₃₅₅, specific ultra violet absorbance at 254 nm, fluorescence index and biological index were 1.36-2.58 m^-1(mean (1.78±0.33) m^-1), 3.10-3.38 L/(mg·m) (mean (3.20±0.08) L/(mg·m)), 1.57-1.69 (mean 1.64±0.03) and 1.13-1.34 (mean 1.19±0.06), respectively. The stable carbon isotopes and spectral parameters suggested that chromophoric DOM, fluorescent DOM, and the overall DOM share similar organic source, and was influenced by both endogenous substances such as planktonic algae and humic organic matter from land-based sources. Comparison with other lakes revealed that absolute values of spectral parameters were mainly used to determine the overall background characteristics of DOM, while fluctuations in the parameters may characterize changes in lake water DOM. In terms of spatial distribution, the relative contributions of fresh endogenous DOM in surface waters from the lakeshore were associated with high primary productivity due to nutrient inputs from agricultural activities in the north. Meanwhile, the water bodies in the lake central area were characterized by residual DOM reflecting a stronger humification, largely due to lower contribution of fresh endogenous DOM. In terms of vertical variabilities, higher DOM degradation was observed in the water column at the lakeshore site, and the additional inputs of endogenous DOM from surface eutrophication being eliminated to a certain extent during the water column process. Although the DOM in the lake central area was influenced by multiple factors, the overall changes of DOM in the water column in the lake central area were relatively small. Therefore, primary productivity under lacustrine eutrophication condition contributes directly to lake DOM carbon pools, but mainly at the surface layer and in a relatively short-term manner. In the long-term perspectives, the lacustrine eutrophication does not have significant impact on the long-term organic carbon pool in the water bodies. In addition to being influenced by primary productivity and organic matter sources, the properties of DOM, such as geography, hydrology, and ecological environment, also have significant impacts on DOM.