[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.