Abstract: In this paper, the variation of the Normalized Difference Vegetation Index (NDVI) in the oasisdesert ecotone in Qira County, Xinjiang during the period from the year 2001 to 2010 was analyzed so as to understand the variation of spatial structure of the oasisdesert ecotone. Moreover, the effects of natural environment and human activities on the variation of NDVI were discussed. The results are as follows: ① In general, the vegetation coverage decreased gradually from the oasis to the desert. Groundwater level was the most important factor affecting the variation of vegetation in the oasisdesert ecotone in Qira County. The variation of vegetation near the oasis was higher than that far away from the oasis, because the zone near the oasis was affected by irrigation water, and such effect was decreased with the increase of distance away from the oasis. In the oasisdesert ecotone, the distribution of vegetation is patchy. There were some mobile or semimobile dunes among the vegetation patches, and the vegetation coverage was extremely low. Based on the variation of vegetation coverage, the oasisdesert ecotone was divided into three types, i.e., the unidirectional graded type, bidirectional graded type and mutant type; ② There was a rapid shift of the oasisdesert boundary during the period from 2001 to 2010, and such shift was mainly affected by human activities. Boundaries of the desert and the oasisdesert ecotone were far away from the Qira Oasis, the impact of human activities on them was low, and the outer boundary was mainly affected by natural factors; ③ Although there was the excessive exploitation of groundwater and land reclamation in the ecotone, vegetation in the ecotone was improved to some extent, its stability was basically maintained, and its coverage was slightly increased because of closing the hillsides for facilitating afforestation and grass planting; ④ Variation of vegetation coverage in the ecotone was consistent with the change of annual precipitation. There was a poor correlation between annual temperature and NDVI. Vegetation in the ecotone was also impacted by aeolian sand disasters.

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