Abstract: Abstract: In order to gain a deeper understanding of the law of element exchange and nutrient restriction in the constructed wetland system of the waterfront basin of plateau lakes, 30 sampling points were set up along different functional areas by taking the constructed wetland in the Jianshan River Basin of Fuxian Lake in central Yunnan as the research object, and the ecostoichiometry characteristics of water, soil and plants in seven sub-districts of the wetland were analyzed by means of correlation analysis and regression analysis. The results showed that the nitrogen removal rate increased step by step and the phosphorus removal rate fluctuated gradually, indicating that the purification effect of TN and TP at the end of the constructed wetland was more obvious. The soil C/N, N/P and C/P ranges of ecological grit pond were 1.29~2.33, 3.50~4.32 and 4.61~8.34, respectively, and the soil C/N, N/P and C/P ranges of wetland were 0.77~3.81, 2.14~11.26 and 4.61~82.97, respectively. Compared with the regional-scale study of wetland ecosystems in China, the soil C content of constructed wetland in this study < the average level of typical wetlands in China, the N and P contents > the average level of typical wetlands in China, and the range of soil stoichiometry ratio < the average level of typical wetlands in China. Plant C content < average level of typical wetlands in China, and N and P contents > average level of typical wetlands in China. Carbon assimilation efficiency of wetland plants in the early stage: Typha orientalis> Thalia dealbata > Canna indica L. > Cyperus alternifolius, carbon assimilation efficiency in the later stage: Cyperus alternifolius > Canna indica L > Thalia dealbata > Typha orientalis, soil mineral metabolism and organic matter decomposition capacity: Cyperus alternifolius > Typha orientalis > Thalia dealbata > Canna indica L. Studies showed that exogenous nitrogen input inhibited soil carbon enrichment and plant carbon transformation. Soil nitrogen availability> phosphorus, phosphorus-restricted > nitrogen. There was a significant positive correlation between soil C-plant C and soil N-plant N in constructed wetlands, and there was no significant correlation between soil and plant P. This paper explores the ecostoichiometry characteristics of nutrients between water-soil-plants, and provides data support and promotion reference for revealing the biogeochemical cycle process of constructed wetlands and the protection of water environment in plateau lake water bodies and lakeside basins.