As an important water source in Shandong Province, Lake Dongping is one of the most important inland lakes to South-to-North Water Diversion East Route Project. We tried to provide the basis for real-time monitoring of water quality mutation by using CDOM absorption characteristics. The average values of CDOM absorption coefficients ［a(280), a(350), a(440)］ were (12.90±1.17), (3.11±0.40) and (0.65±0.09) m-1. a(440) had linear relationships with total nitrogen (p<0.01), total phosphorus (p<0.001), dissolved organic carbon (p<0.001), chemical oxygen demand (p<0.001), Chlorophyll a (p<0.001), which can be used to estimate the water quality parameters. The results showed that CDOM absorption coefficient reflects the nutritional status of Lake Dongping, which is close to eutrophication level. There was an obvious decrease of CDOM absorption coefficients from river mouth of Dawen River to lake center and then to the outlets of lake. This illustrated that terrestrial input is the main source of nutrients and pollutants in Lake Dongping.