Vegetation connects soil,air and water,and is an important "indicator" in global changes. Heihe River basin is located in the arid region of northwest China where climate is volatile. Spot-Vegetation NDVI, meteorological and regional groundwater depth data from 1998 - 2008 were fed into ENVI, Arcgis software to dissect response correlation between annual NDVI and climate elements, response correlation between NDVI of different vegetation types and groundwater depth. It was found that vegetation coverage in Heihe River basin has increased the most in the spring. NDVI spatial distribution indicated that the up and middle streams had marked increase. Index of vegetation coverage declined downstream. Groundwater level in Heihe River basin has declined, annual groundwater depth changed from 3.09 m to 4.67 m. The place where underground water depth was deeper mainly concentrated in the upstream basin around Zhangye farm, which showed the deepest underground water depth. Groundwater depth in the downstream region was generally shallow. Index of vegetation coverage correlated positively with temperature and negatively with groundwater depth. Comprehensive analysis of inter-relationship among NDVI, climate,and groundwater may lead to quantitative correlations.