Exploring the evolution of water quality purification triggered by land use change is important for protecting and improving water quality and achieving sustainable development. Taking the "Two Lakes and One Reservoir" basin as an example, the patch-level land use simulation (PLUS) model and the integrated valuation of ecosystem services and tradeoffs (InVEST) model ecosystem service water quality purification module were used to simulate changes in the spatial and temporal patterns of land use types as well as the characteristics of water quality purification of the basin under future natural development scenarios and ecological protection scenarios based on the land-use data for the years 2000, 2010 and 2020. The response relationship was quantitatively reveal between land use change and water purification function. The results show that the land type of the "Two Lakes and One Reservoir" basin is dominated by arable land, and in 2030, the area of arable land, forest land and grassland under the natural development scenario shows a decreasing trend, and the area of construction land shows an increasing trend, and the ecological protection scenario can effectively protect the spatial distribution and area of the basin' s arable land and forest land, etc. The TN and TP outputs of the "Two Lakes and One Reservoir" basin are dominated by the low-intensity outputs, and the outputs of TN increase firstly and then decrease, and TP outputs increase year by year during the period of 2000—2020. From 2000 to 2020, TN output first increases and then decreases, TP output increases year by year, and the water purification capacity shows a steady trend. In 2030, TN output continues to decrease under the natural development scenario, and TP output shows an upward fluctuation, and TN and TP output under the eco-protection scenario is reduced compares with that under the natural development scenario, and the eco-protection scenario can increase the water purification capacity. Ecological land types can effectively intercept N and P into the water body, and the ecological protection scenario effectively reduces the rate of change of ecological land types and reduces the output of TN and TP. The future planning of the "Two Lakes and One Reservoir" basin should increase the proportion of ecological land, and increase the ability of land types to intercept TN and TP.