Abstract: Based on the method of Lakes comprehensive nutrition state index TLI(Σ), water quality monitoring data of Nanhu Lake from 2004 to 2018 was used to evaluate water quality of nutritional status in Nanhu Lake and then analyze its relationship with meteorological factors. It was shown that TLI(Σ) in Nanhu Lake had an increase trend during the years of 2004 to 2008, and the TLI(Σ) reached the maximum in 2008 when an outbreak of algae blooms first occurred, then there was a decrease trend after 2010. The TLI(Σ) showed obvious seasonal fluctuations with the maximum in summer and the minimum in winter. For the monthly TLI(Σ), it reached the maximum in July and the minimum in October. Compared with the Huxin station in the center of Nanhu Lake, the Maizigang station had higher TLI(Σ). It should be related with stronger human activities. TLI(Σ)and air temperature, sunshine time, wind speed had significantly positive correlation, but the air pressure was significantly negatively correlated with the TLI(Σ). In spring and summer, temperature and sunshine were the dominant factors for causing the eutrophication of Nanhu Lake.