The thirteen lake water bodies in twelve parks in Shanghai were investigated in Aug. 2011. The weights of the single water quality factor in the comprehensive water quality index have been improved and selected. The comprehensive water quality identification index method was used to evaluate the water quality nutrition status of the investigated water-bodies. The rationality of the comprehensive water quality identification index method applied to the lake eutrophication assessment was verified by scoring method and comprehensive nutrition state index method. The conclusion showed that only 15.4% of the comprehensive water quality of the park lakes met the requirements of water environment function, the lakes bing in eutrophication status accounted for 53.8%. The most serious pollutants were total nitrogen and chemical oxygen demand. The comprehensive water quality identification index method was simply used and can fully reflected the status of the water quality, the evaluation results were scientific and reasonable, it is appropriate for application to the eutrophication evaluation in park lakes.