Abstract: The source of the Yangtze River is located in the remote and high-altitude Qinghai-Tibet Plateau, where the ecosystem is fragile. Influenced by global climate change and human activities, various elements closely related to the ecological system of the source area, such as glaciers, permafrost, swamps, wetlands, and vegetation, have experienced different degrees of degradation, which has aroused widespread concern from various sectors of society. This article analyzes the spatiotemporal evolution characteristics of the climate and ecological vegetation in the Yangtze River source region using long-term, high spatiotemporal resolution meteorological and MODIS NDVI data, combined with mathematical and statistical methods, and explores the response mechanism of vegetation to climate and soil water. The results show that over the past 40 years, the rainfall and surface temperature in the Yangtze River source region have decreased from southeast to northwest, and the temperature in each region has generally increased. Vegetation growth in the eastern region is better than that in the western region, and since 2000, the overall vegetation growth in the Yangtze River source region has gradually improved. Due to the sensitivity of permafrost to temperature, vegetation growth during the growing season in the Yangtze River source region is more affected by temperature than rainfall. The ecological vegetation in the Yangtze River source region is greatly influenced by soil water content, and the degree of influence gradually weakens from the surface to the deep layers.