Abstract: The upper reaches of Minjiang River play important roles in resource support, ecological service, and environmental regulation. It is the soil erosion sensitive control region of the national ecological red line and an important natural basis for the survival and development of the country. At present, the spatial superposition of the ecological, economical, and social processes in this region not only affects resources, environmental, and ecological functions but also poses a serious threat to the ecological security and regional sustainable development of the Minjiang River basin and even the upper reaches of the Yangtze River. Recognizing and understanding the temporal and spatial variation of vegetation Normalized Difference Vegetation Index (NDVI) and its topographic response mechanism in the upper reaches of Minjiang River and analyzing the best topographic position of vegetation changes can provide direction, guidance, and scientific reference for ecological environmental construction in this region. In this study, the spatial and temporal changes of vegetation NDVI in the upper reaches of Minjiang River were analyzed using remote sensing and GIS technology. Through spatial overlay analysis, the response of spatial-temporal variation of NDVI to topographic factors such as elevation, slope, aspect, and topographic relief was discussed in detail. Combined with the distribution index of different types of vegetation change, the regional differentiation rule of vegetation change under the background of different topographic factors was further defined, and the best topographic position of different types of vegetation change was obtained. The results showed that: (1) vegetation coverage in the upper reaches of Minjiang River was good and stable, and approximately 26.62% of the vegetation increased significantly, while only 1.21% of the vegetation decreased significantly during 2000-2020. (2) The types of vegetation change had significantly different distribution patterns under different topographic positions, such as elevation, slope, aspect, and relief degree. Overall, the area proportion fluctuated slightly under different topographic positions, and the distribution index was different. (3) The best topographic position of the regions with significant vegetation degradation was the "dominant" zone, which was affected by human activities and the "inferior" zone, which was restricted by natural conditions. The best topographic position of the regions with significant vegetation growth was mainly distributed in the areas with relatively low elevation, large slope, and relief and shady slope of human settlement radiation.