Soil salinization is a serious problem in Yanqi basin，Xinjiang Wei Autonomous Region、and the agricultural development and the ecological environment are threatened.Based on analysis of the chemical composition of salt-affected soil and statistical analysis of its spatial distribution，it is concluded that:(1)the salt type involved in soil salinization is chlorinate-sulfate and about 60% of land is strong salinizated and saltier;(2) soil salinity is greater in natural areas than in farmland areas;(3)soil salinity increases from the fringe of the torrential fan to the shore of salted lake.In irrigated areas，soil salinity changes seasonally and decreases as a whole because of irrigation and drainage.The reasons for soil salinization include natural factors and human activity.Water-saving irrigation，rational groundwater exploitation and improved irrigation and drainage systems are effective measures to control soil salinization.