In the different land types,the different natural vegetation communities exist,which the dominant species are also different.Here on the basis of land use types from two phrases of TM satellite image,the dynamic changes of natural vegetation in the northeastern Ulanbuh Desert were analyzed.The main results are that the area for fixed sand land and semifixed sand land decrease,and the mobile sand land increase,and the salinate fields also shrunk.Subsequently,the ecological water uses for natural vegetation were calculated with indirect method.The following results are presented.The ecological water use for Caragana community is about 50.01 percent of the total water use,Artemisia Nitraria Ammopiptanthus community is 41.03%,Haloxylon community 7.38%,and Tamarix community in salinate fields is about 1.58%.