Taking Yangzonghai Lake as the research object,using landsat-8 OLI remote sensing image and chlorophyll a concentration measured data,based on band sensitivity analysis,a chlorophyll a concentration estimation regression model was constructed. The results show that the polynomial regression model with the band combination (B5-B4))/((B5+B4) as the parameter has the best result with a fit of 0.7201. The inversion obtained the spatial distribution map of chlorophyll a concentration and eutrophication index of Yangzonghai Lake on March 1,2018. The results showed that the Yangzonghai Lake was in a medium nutrient state.