Abstract: The hilly area of central Sichuan is an important ecological barrier in the upstream of the Yangtze River and is also a key implementation area of two improtant projects, namely “Returning Farmland to Forests and Grassland projects ” and “ Natural Forest Protection Project ”.However，recent years there was a great change in vegetation cover and ecology in this area, which is regarded as a consequence of climate change and human activities. Based on the multi-temporal MODIS NDVI data， Meteorological data，Land cover map and other statistical data of the study area, and using maximum value composite (MVC), linear regression and correlation coefficient, this paper aimed to analyze the dynamic changes of vegetation between 2005 and 2015 after introducing the national ecological engineering project, and to identify the impacts of climate change and human activities on the vegetation. The results showed that the vegetation cover in the hilly areas of central Sichuan has been improved, with a rate of 5.84/10 a (P<0.01). NDVI increased siginificantly for 31.58% vegetation area and this change was found in the middle reaches of the Jialing River and in the middle and lower reaches of the Minjiang River; by contrast, NDVI decline for few areas (2.90%), which occurred mainly in the city center and surrounding areas. Vegetation in study area was more sensitive to precipitation compareing its sensitivity to temperature. NDVI showd a siginificant correlation with precipitation for 22.08% of the total study area, while NDVI siginificantly correlation to temperature for 7.69% of the total study area. NDVI of forest, shrub and grassland increased significantly by 60%, while the type of land-use where vegetation NDVI degraded was mainly construction land. The implementation of the“Returning Farmland to Forests and Grassland” and “Natural Forest Protection Project” has played a positive role in improvement of vegetation cover in the hilly area of central Sichuan.