As a comprehensive representation of human activities, landscape pattern evolution affects the location, migration path and transformation process of non-point source pollutants by changing the hydrological process and flow path, and thus has a profound impact on the water environment of the basin. As one of the main rivers entering Lake Taihu, Tiaoxi River plays a critical role in the water environment of Lake Taihu. In this paper, the upper reaches of Dongtiaoxi River originating in Taihuyuan Town, Lin'an District, Hangzhou City is taken as the research area. Based on the monitoring of river water quality in two periods, by integrating landscape component indexes and landscape spatial configuration indexes, methods like correlation analysis, redundancy analysis and stepwise regression analysis are used to quantify the interpretation ability of landscape indexes to different water quality indexes and discuss the response pattern of river water quality to the watershed landscape pattern on the sub-watershed scale. The results show that: 1) The total nitrogen (TN) concentration far exceeds the surface water quality class V standard limit at most sampling sites in the upper reaches of Dongtiaoxi River, but the concentrations of ammonia nitrogen (NH₃-N) and total phosphorus (TP) are generally low, and some sampling sites could reach class I water quality standard. 2) During the flood season, in landscape composition, the proportion of “Source” landscape in the basin is an important contributor to water quality. Farmland has a significant positive correlation with nitrate-nitrogen (NO^-₃-N) and TN concentration, while construction land impacts NH₃-N and TP concentrations; in non-flood season, the water quality is dramatically impacted by landscape configuration factors, especially the perimeter-area fractal dimension characterizing the patch shape. 3) Whether in flood season or non-flood season, forest and grassland can remarkably reduce pollutants in rivers, acting as the key “Sink” landscape for the prevention and control of river pollution in the basin. 4) On the whole, nitrogen and phosphorus pollution in the river is closely related to the intensity of human activities. The water environment of the river can be effectively improved by increasing landscape connectivity and lowering the fragmentation of the natural landscape.