Desertification taking place in arid area is often related with vegetation deterioration in lower reaches of interior river. In the cause of it, the soil characteristics changed regularly due to less surface water and ground water lowing, which cause soil drying and salinizing. Through the analysis and comparison of soil characteristics in different sites with different desertification degree revealed the trend of soil water content, soil salinity, organic matter, soil texture, as well as changing trend from bog soil, meadow soil to adobe soil, halomorphic soil. These changes were accelerated as the vegetation ruined and lead to land desertification. The process of changing from autochthonous soil to adobe soil can be divided into different stages which differ in changing speed, i.e., the formation of climax soil will last long time. But, once its loss the stability, desertification will develop rapidly. Studying the possibility for the converse changes of
climax soil is significant to vegetation restoration and should become a research direction in the future.