Landscape compositions and patterns determine the sources of pollutants and the potential in interception and absorption of the surface landscape. Meanwhile, the surface slope will aggravate soil erosion. Therefore, the sloping landscape characteristics are important factors affecting riverine water quality. Based on the water quality monitoring data of the Chongqing section of the upper Yangtze River in 2015 and land use data with a spatial resolution of 30 m, this study firstly extracted landscape patterns and compositions at six scales:100, 200, 300, 500 and 1000 m river buffers and sub-watershed. We further classified the landscape compositions into three different slope scales (i.e., total land class, gently sloping land class and steep sloping land class). Furthermore, correlation analysis and redundancy analysis (RDA) were used to quantitatively explore the multiple spatial and temporal impacts of sloping landscape features. The results showed that:(1) the influence of sloping landscape features on riverine water quality exhibited a spatial scale effect. The influence was stronger at the riparian scale than the sub-basin scale with the conditions of key scale ranging from 100 m to 300 m in the riparian zone, and the most effective scale of 200 m riparian. (2) The seasonal differences in riverine water quality affected by sloping landscape features varied with the spatial scale. The flood season was stronger at the 100 m to 300 m riparian scales than the non-flood season, and the opposite in the 1000 m riparian scale, whilst, there was no seasonal difference at the sub-basin scale. (3) The ratio of construction was positively correlated with dissolved oxygen (DO), permanganate (COD_Mn) parameters, and the percentage of cultivated field was positively correlated with ammonia nitrogen (NH₄⁺-N), both of which were "source landscapes" of water quality pollution. The explanation rate of sloping cultivated land on water quality was higher than that of total land type cultivated land. Forest was negatively correlated with water quality parameters, which had a positive effect on mitigating water quality deterioration. (4) The patch cohesion index (COHESION) and aggregation index (AI) were positively correlated with NH₄⁺-N, while patch density (PD) and edge density (ED) indicators were also positively correlated with DO and COD_Mn. In summary, strengthening sewage treatment technologies for urban, planting protective forests in the riparian zone, adopting cross-slope farming and optimizing the landscape structure can enhance the absorption of pollutants and effectively prevent the concentrated output of pollutants within the watershed (especially within 300 m riparian zones), which is of great significance to the prevention and control of water pollution in rivers.