The southwest arid-hot valley, located in the heart of the Hengduan Mountain Range, is an ecologically fragile region in China, deeply influenced by climate, topography, and human activities. These factors contribute to a highly variable vertical vegetation distribution pattern, with distinct vegetation types at different altitudes. At lower altitude area, sparse shrub and grass ecosystems prevail, while at higher altitude area, more developed and diverse forest vegetation systems thrive. This unique ecological distribution is characteristic of the southwest mountainous region, which is renowned for its rich biodiversity, complex ecosystems, and environmental sensitivity. The southwest arid-hot valley is considered one of China’s most vulnerable ecological zones, especially due to the ongoing impacts of climate change, human encroachment, and other environmental pressures. This study employed satellite remote sensing data from Landsat imagery spanning three decades (1990—2020). Utilizing the Google Earth Engine (GEE) platform, the research analyzed key environmental variables, including the normalized vegetation index (NDVI), land surface temperature (LST), and the temperature vegetation drought index (TVDI), to examine how vegetation coverage has changed over time in response to various ecological factors. The findings revealed notable spatial and temporal shifts in vegetation coverage, offering valuable insights into how ecological systems in this region have responded to both natural environmental changes and human-driven factors such as land use changes and climate alterations. Over the past 30 years, both air and surface temperatures have risen significantly, with higher altitude area experiencing more pronounced warming than lower altitudes. This temperature rise has had a direct and significant impact on vegetation growth patterns. NDVI data showed a general increase in vegetation coverage, with alpine forest ecosystems exhibiting a higher growth rate (0.0077/a) compared to shrub and grassland ecosystems (0.0027/a). This indicates that forest ecosystems, particularly at higher altitudes, have been more responsive to the changing climate than lowland ecosystems. Topographical factors, such as altitude, slope direction, and gradient, play a crucial role in shaping vegetation dynamics. These factors create varying hydrothermal conditions across the region, leading to significant differences in vegetation types at different elevations. The study also identified that the primary driver of increased vegetation coverage was the rise in air and surface temperatures. In low-altitude areas, vegetation coverage increased most rapidly when surface temperatures reached around 20°C, whereas in high-altitude regions, the optimal temperature for vegetation growth was found to be approximately 15°C. Beyond these thresholds, the rate of vegetation increase slowed, indicating diminishing returns at higher temperatures. This study offers valuable insights into the driving forces behind vegetation changes in ecologically sensitive regions, especially under the pressures of climate change, using satellite imagery and the GEE platform.