Abstract: The Inner Mongolia reach of the Yellow River basin is suffering severe degradation as an ecological barrier at present. Analyzing its landscape pattern and ecological risk is of great significance for promoting the high-quality development of this reach. Based on the land use data of 1980, 2000, and 2020 of the study area, this study analyzed the spatial distribution and spatio-temporal evolution of the ecological risks by calculating the regional landscape pattern index and the ecological risk index. The results show that: ① During 1980—2020, the land in the study area was dominated by grassland, which accounted for more than 50%. In this period, the areas of cultivated land, grassland, water areas, and unused land decreased by 578 km², 1 911 km², 383 km², and 255 km², respectively. By contrast, the areas of forest land and construction land increased by 1 055 km² and 2 072 km², respectively. In terms of land use types, the land in the study area mainly shifted from grassland, cultivated land, and water areas to construction land and forest land. The comprehensive land use intensity during 2000—2020 was 0.85 percentage points higher than that during 1980—2000; ② During 1980—2020, the patch number of all types of land decreased except for water areas and unused land; the degree of landscape fragmentation of all types of land increased except for construction land; the degree of landscape disturbance of all types of land decreased except for forest land; the degree of landscape loss of all types of land did not change significantly except for construction land, for which the degree of landscape loss decreased significantly; ③ The ecological risk value of the Inner Mongolia reach of the Yellow River basin showed a downward trend during 1980—2020. Areas with fairly low and low ecological risks increased by 9 000 km² in total and were primarily concentrated in the northern and central areas in this period. In contrast, areas with high and fairly high ecological risks decreased by 1 350 km² in total and were scattered on the eastern and northern edges.