Abstract: The study on the temporal and spatial evolution of vegetation NDVI and its topographic differentiation effect is of great significance for deeply understanding the relationship between vegetation and human activities, revealing the changes of regional environment and guiding the scientific governance of regional ecological environment. The upper and middle reaches of the Yangtze River Basin was chosen as study area. Based on yearly annual normalized difference vegetation index(NDVI) derived from SPOT sensor, DEM and basic geographical information, the temporal and spatial evolution characteristics and topographic differentiation effect of vegetation NDVI in the middle and upper reaches of the Yangtze River Basin are discussed, and the reasons for its influence are discussed. The results show that:① The ecological environment in the middle and upper reaches of the Yangtze River Basin has been greatly improved from 1998 to 2015. The average annual NDVI of vegetation increased from 0.67% in 1998 to 0.75% in 2015, with an average annual growth rate of 0.57%.② The spatial improvement area of vegetation NDVI (56.82%) was significantly larger than that of degraded area (7.3%), and the improvement area was mainly distributed in the middle and eastern part of the study area. ③ The improvement trend of vegetation NDVI was the highest in the area of 500~1 000 m, 1 000~1 500 m and slope of 8°~15°and 15°~25°, and the degradation trend was the highest in the area of >5 000 m and slope 0°~5 °, and the slope aspect had no significant effect on the change of vegetation NDVI. ④The change of vegetation NDVI in the middle and upper reaches of the Yangtze River Basin from 1998 to 2015 may be the result of the implementation of ecological projects such as natural forest protection, conversion of farmland to forest (grass) and human social and economic activities. ⑤This paper can provide a scientific basis for the treatment and improvement of the fragile ecological environment in the middle and upper reaches of the Yangtze River Basin, and then build an important ecological barrier in the middle and upper reaches of the Yangtze River, and promote the green development of the Yangtze River economic belt.