It is important to identify the relationship between runoff extremes and landscape pattern because it benefits for collaborative promotion between ecological construction and water resources regulation within a basin. As one of the most important ecologically fragile area in China, the Three Gorges Reservoir Area experienced ecological construction during the last twenty years. In this study, the Dongli River Basin, within northeastern part of the Three Gorges Reservoir Area, was taken as an example. Several methods, including the SWAT (Soil and Water Assessment Tool) model, landscape pattern index, Pearson correlation analysis and Random Forest, were used to analyze runoff extremes response to landscape pattern changes. And then, runoff extremes of driving mechanism were investigated from the perspective of the whole basin and typical subbasin. The results showed as following: (1) Within the whole basin, forest and cropland were the dominant landscapes, area of which increased by 3.76% and 1.82% from 2000 to 2020, respectively. Its landscape became aggregative while landscape diversity and uniformity declined. The dominant landscapes within the subbasin were similar to that within the whole basin. Changes in patch density (PD), largest patch index (LPI) and contagion index (CONTAG) were more dramatic than those of the whole basin from 2000 to 2020. (2) Four indices, including the maximum 1 day (Max1d) runoff, the maximum 7 day (Max 7d) runoff, the minimum 1 day (Min1d) runoff, and the minimum 7 day (Min7d) runoff, were selected as runoff extremes. Within the whole basin, runoff extremes mainly showed decreasing tendency under the landscape pattern changes from 2000 to 2020. Among them, Max1d decreased by 4.44% while Min1d runoff and Min7d declined more than 40%. Due to landscape changes from 2000 to 2020, the changes of Max1d and Max7d within the typical subbasin were higher than these within the whole basin. The changes of Min1d and Min7d within the typical subbasin were similar to these within the while basin. Runoff extremes within the typical subbasin are hinger than these within the whole basin. (3) The regulation ability of landscape pattern on runoff extremes became weak from 2000 to 2020. Due to degradation in forest-grass landscape combination and aggregation in landscape spatial configuration, contribution rate from landscape composition decreased by 0.84%-7.39% and contribution rate from landscape configuration decreased by 1.63%-3.89%. The results can deepen the understanding of the hydrological process to landscape pattern, which can provide scientific basis for the ecological construction and restoration for the Three Gorges Reservoir Area.