Abstract: The Pressure State Response (PSR) model can reflect the impact of socioeconomic conditions on the ecological environment of lake water bodies. Based on the PSR model, an evaluation index system was constructed, which included 18 indicators such as population density, vegetation index, water exchange cycle, and phytoplankton diversity index. The years 1999 and 2007 were selected as the historical control years, and the ecologicalhealth status of Lake Taihu Basin from 2011 to 2020 was compared with the control years. The results displayed: (1) The weights of the state layer, pressure layer, and response layer were 0.418, 0.291 and 0.291, respectively. The indicators that had a greater impact on the ecological health of Lake Taihu Basin were mainly the coverage of large aquatic vegetation, the rate of reaching the standard of total phosphorus in lakes, the proportion of environmental protection investment in GDP, the comprehensive trophic status index (TSI) of lakes, the utilization and development rate of water resources, and the diversity index of phytoplankton, with an overall contribution rate of 51.74%. (2)The ecological health assessment results of Lake Taihu Basin in 1999 and 2007 were unhealthy, and it was generally healthy to healthy from 2011 to 2020. The ecological health assessment index decreased in 2015 and 2017, but the overall health status of the basin was improving in 2011-2020. After 2011, the improvement of Lake Taihu Basin health was mainly due to pollution control, ecological restoration and management of the state and local government. The fluctuation of the basin ecological health index in 2015 and 2017 was mainly due to adverse meteorological factors. (3)Changes of large aquatic vegetation coverage, total phosphorus compliance rate, TSI, and phytoplankton biodiversity index were consistent with the changes of ecological health assessment index and the health level of Lake Taihu Basin. In the past 20 years, the increase of the proportion of environmental protection investment in GDP and the optimization of water resources development and utilization had alleviated the adverse impact of the decline of the four indicators on the ecological health of Lake Taihu Basin to a certain extent.