Abstract: The paper briefly presents the natural general situation of Ejina oasis,analyzes the variation ten dency of surface water and groundwater lasted 20 years in the lower Heihe River basin,dissects the growth of vegetation,succession of plant species,vegetation degree of coverage,the relationship between Ejina oasis and the depth of local groundwater,forecasts the change of Ejina oasis area in the designed years,and points out that the sustainable development of economy and society and environment construction in Ejina oasis rely on water resources.The core issue of Ejina ecology protection is how to steady the oasis and make it moderate expanding,which has important stratagem significance.