Abstract: The relationship among different nutrients and the relationship between the nutrients and algae growth in Nanhu Lake were comprehensively analyzed.The influences of various environmental factors on the eutrophication in Nanhu Lake were investigated and the main contrtolling factors of the eutrophication in the lake identified,combined with experiments of algae growth potential.It was shown that the main controlling factors of eutrophication in Nanhu Lake are light,temperature,carbon and nitrogen while the control of phosphorus is key to the control of eutrophication in Nanhu Lake.