Vegetation plays an important role in the terrestrial ecosystem. Under the background of global warming, the response of vegetation cover to climate change has become an important research field. Normalized Difference Vegetation Index (NDVI) is commonly used to study the response of vegetation change to temperature and precipitation on a regional scale. In recent years, the frequent occurrence of extreme climate events has increased the risk and vulnerability of terrestrial ecosystems and endangered ecological security. Shaanxi province is located in the hinterland of China, with a large north-south span and obvious regional differences in hydrothermal conditions and surface ecological environment. Therefore, it is necessary to study the dynamic change of NDVI and its response to extreme climate, which can provide theoretical evidence of ecosystem evolution and ecological environment conservation in Shaanxi Province. Based on MODIS NDVI data from 2001 to 2018, the spatio-temporal variation pattern of NDVI was analyzed from the perspective of different ecological areas in Shaanxi Province. The response characteristics of NDVI to extreme temperature and precipitation indices were also discussed by using the daily meteorological observations from 31 stations in this region. The results showed that (1) the variation of NDVI increased significantly and the spatial difference of NDVI value was obvious in Shaanxi Province and its ecological areas. The high value of NDVI distributed in the south, whereas the low value of NDVI distributed in the north. The decreasing order of the value of NDVI of the different ecological areas was as follows:ecological region of deciduous and broad-leaved forest in Qinba Mountain (IV) > agricultural ecological area of Fenwei Basin (III) > agricultural and grassland ecological region of the Loess Plateau (II) > typical grassland ecological area in northern Shaanxi (I). Meanwhile, the lowest value of NDVI was 0.38 and the highest value was 0.86. (2) The correlation between NDVI and extreme climate indices showed that annual NDVI in each ecological area was significantly positively correlated with TN90p and extreme precipitation indices. However, extreme precipitation had an important impact on vegetation growth in the north of Shaanxi Province, and extreme temperature was the main factor in the south. (3) On the monthly scale, the NDVI had a significant lag time of 3 months with extreme temperature indices, including TMIN_mean, TN_n, TX_n, TMAX_mean, TN_x, and TX_x, while had a lag time of 2 months with extreme precipitation indexes in each ecological area. In general, the results effectively revealed the response of vegetation to climate fluctuations in Shaanxi Province.