Due to water reduction, the area of oasis degraded rapidly, and many eco-environmental problems have emerged in the lower Heihe River. For the sake of improving the eco-environment, and deterring the trend of further degradation of the oasis, the water transport project in the lower reaches of the Heihe River was carried out in 2000. According to the water line, there are great changes of temporal and spatial distribution of water resources in the lower Heihe River in the past nine years. As a result, the vegetation in the lower Heihe River also changed. In order to objectively evaluate the influence of water regulation on vegetation in this region, in this paper, by means of field surveys and remote sensing, the response range and extent of the groundwater were described, and the variation of natural vegetation in the lower reaches as a result of change of the groundwater level were also described in about five years, and the rules of groundwater response to the ecological water transport were analyzed preliminarily. These results show that there are obvious effects of water regulation on the vegetation, and that the eco-environment is experiencing a good change in the lower Heihe River.