Through making field investigation and using the results of 2000 TM images classified, the distribution patterns and development trend of land sandy desertification as well as its causing negative affection were analyzed in this paper. In the view of the spatial distribution and temporal variation of climatic factors and the relation be- tween mankind and earth, the driven factors of occurrence and development of land sandy desertification was ex- plored. The results showed that the spatial distribution of land desertification was different with the scope of the wind erosion climatic factor in spring; that the development rate of land sandy desertification disagreed with the variation of three main climatie factors. The final conclusion drew is that the main reason of land sandy desertifica- tion in study area in the last 50 years isn't the temporal and spatial variation of climatic factors. The real reasons are the serious unbalance between the pressure coming from man and livestock and the environmental capacity; the worse management on the relation between human and land; the unenlightened and extensive produetion and living styles.