Abstract: The Chishui River Basin, located in southern Guizhou Province, serves as a critical water conservation area. Evaluating the spatial and temporal trends of landscape ecological risks and analyzing the primary driving factors are essential for maintaining ecological security and promoting sustainable development within the basin. This study focused on the Guizhou section of the Chishui River Basin and utilized land use data to assess and analyze the spatiotemporal characteristics of landscape ecological risks. Geographic detection methods were used to identify the drivers of these risks. First, forest land was the predominant landscape type, concentrated in the lower reaches of the basin. Cultivated land occupied a significant portion of the total area, with contiguous patches appearing predominantly in the northeastern region. Construction land showed an increasing trend, particularly in Renhuai City, where it was mainly distributed in liquor industrial parks. The unused land and water areas remained relatively small with minimal spatial changes, whereas grassland was scattered throughout the basin with insignificant changes. Second, from 2000 to 2020, the landscape ecological risks in the study area were primarily categorized as medium. The basin features typical karst and Danxia landforms with a steep terrain, whereas the areas along the Chishui River have a relatively flat topography and abundant biological resources. Human activities along rivers lead to high levels of interference. High-risk areas, mainly concentrated along the Chishui River, were characterized by dense populations, relatively flat terrain, and economic development. Over time, high-risk areas decreased in Jinsha County and Qixingguan District, whereas in Renhuai City, they shifted from south to north, primarily within the liquor industrial parks. Low- and medium-low-risk areas, predominantly found in the northern and southern parts of the basin, were characterized by forested vegetation, rich natural resources, limited economic activities, and stable landscape ecosystems. Third, in terms of landscape ecological risk changes, 60% of the regional landscape ecological risk levels remained unchanged, indicating stable ecosystem conditions. Initially, the landscape ecological risk increased before decreasing, with areas of reduced risk concentrated near the Chishui River. Areas with increased risk were less common and mainly distributed in the urban areas of Xishui County, Chishui City, tourist zones, Renhuai City, airports, and wine parks. Regions without notable changes in risk levels, characterized by better natural ecological environments, were located in the northeastern part of the basin and central-eastern Qixingguan District. Fourth, variations in landscape ecological risk within the basin were affected by multiple factors. For example, human interference related to socioeconomic conditions and average annual precipitation associated with natural elements significantly affected the landscape ecological risk in this region, and these driving factors exhibited nonlinear relationships characterized by dual enhancement effects.