A quantitative relation between light attenuation coefficient and water transparency was established based on the principle of water optics; described the relationship between nitrogen-phosphorus nutrients and algae based on the principle of mass conservation; constructed an eutrophication model accounting for the interaction effect of light and nutrients, which coupled the driving mechanisms of light and nutrients on algae growth. The model was calibrated and verified using water quality data monitored from April to July 2015 in the Meihu Lake. The model was then used to analyse the effect of change in light-nutrient content on algae growth, under different scenarios. Results showed that the algae had a good growth tendency under different light-nutrient conditions which was simulated by the established eutrophication model; there was an inhibitory action for algae under low light intensity when the nutrient concentrations increased, the effect of TP concentration was more important than TN concentration on algal growth when nutrient concentrations increased the same multiple; as a whole, algae growth is more affected by light intensity than nutrients, and more affected by total phosphorus than total nitrogen. The best scenario for algae growth is where illumination is 89.6klx, TP concentration is 0.168mg/L and TN concentration is 2.72mg/L.