Watershed landscape characteristics determine the sources of pollutants and the absorption potential of the surface landscape, but we still lack the knowledge of their relation from different spatial scales in the whole watershed. Based on the land use type interpreted by Landsat 8 OLI remote sensing image in 2020 and combined with the water quality index data of monitoring points, the influence of landscape characteristics on river water quality at different spatial scales including sub-watershed, river buffer zone and circular buffer zone of monitoring points was discussed using mathematical statistics and GIS spatial analysis method. The results show that:(1) the landscape composition is different at different spatial scales. At sub-watershed scale, forest land is the main land use type. At river buffer zone and circular buffer zone, cultivated land are the main land use type. (2) The cultivated land, construction land, other land and garden land are positively correlated with water quality index COD_Mn, BOD₅, which are the contribution sources of water quality pollution in the Nanliu River Basin. The increase of grassland, forest land and water area is generally beneficial to the improvement of river water quality, especially at the scale of river buffer zone. PD, CONTAG, SHDI and SHEI are the main factors causing river water quality change. (3) Landscape characteristics of river buffer zone had the greatest impact on water quality, followed by sub-watershed scale and circular buffer scale according the total explanation rate of redundancy analysis. To economically protect water quality in the Nanliu River, we should focus on riparian zone within 50 m and decrease the cultivated land area and optimize its landscape structure.