Soil salinization is one of the main forms of land desertification.Therefore,study on the dynamic changes of soil salinization is very important for land management and utilization.Soil salinization information in the Manas River basin was extracted from four sets of Landsat TM/ETM+images in 1975,1990, 2000 and 2014.Then spatiotemporal dynamic changes were analyzed using statistical and spatial analysis methods.The results show that:(1)the severe salinization area reduced by 2 369.4 km~2;the moderate salinization area remained stable;the slight salinization area increased by 1 408.0 km~2;and the cultivated land area increased by 3 443.5 km~2 from 1975 to 2014;(2)the distribution of soil salinization had the obvious spatial characteristics,with the severe and moderate salinization areas mainly distributing around the reservoir in the middle reaches and around the Gurbantunggut Desert in the downstream,mild salinization embedded in the cultivated land;(3)the degree of soil salinization had increased from 1975 to 1990,decreased from 1990 to 2000,and deteriorated from 2000 to 2014;(4)valid policy and economic measure are effective to improve the management of soil salinization. With the global climate warming,the continuous expansion of cultivated land area,and the unreasonable utilization of water resources,the uncertainty of soil salinization change will increase.