[Objective] The spatial distribution characteristics of vegetation and ecological change trends under different topographic and geomorphic units in Qaidam Basin was explored in order to provide decision support and data basis for the local formulation of targeted ecological environmental protection strategies. [Methods] Based on the five-phase Landsat remote sensing image of the Qaidam Basin from 1998 to 2018, the variation characteristics of the normalized vegetation index (NDVI) of different geomorphic units in the area were studied by using trend lines and related analysis methods, and their driving factors were analyzed. [Results] ① NDVI in the basin was generally high in the southeast and low in the northwest. From 1998 to 2003, due to the impact of natural disasters such as rock avalanche, landslides, and debris flows, NDVI showed a significant downward trend. From 2003 to 2008, with the strengthening of national ecological environment governance and the improvement of public awareness of environmental protection, NDVI showed a significant increase trend, and the ecological environment of the basin continued to improve. After 2008, NDVI stabilized and the ecological environment maintained a healthy development. ② Under different landform zones, water sources were the key factors limiting vegetation growth, and vegetation growth in alluvial and flood fan areas was often prosperous. The impact of human activities on the ecological environment was two-sided. In Delingha, middle-altitude flowing water affects hilly platform plain area (Ⅱ₂), human beings changed land use types, planting Lycium barbarum and other economic crops, which made NDVI increase significantly in this area. In the mid-altitude of Dabson, the salt lake sedimentary plain (Ⅱ₃), the NDVI was affected by human salt mining activities, showing a significant downward trend. ③ Affected by climate, human activities and vegetation types, NDVI and altitude exhibited a significant positive correlation. ④ NDVI was obviously affected by the slope gradient. When the slope gradient was 2°~35 °, NDVI was generally higher. [Conclusion] Water source and climate are the key factors affecting vegetation change. The change of human activities and topography will also lead to the change of ecological environment.