The dynamic characteristics of soil salt in salinization abandoned farmland were studied under the covers of Salsola ferganica, Phragmites australis and Halostachys caspica in the irrigation area of arid Manas River in the southern margin of Junggar Basin, and the environmental factors which affect soil salt accumulation and migration were discussed. The results indicated that soil salt content was different greatly under different vegetation covers, the variation coefficients of soil salt content were moderated within 0-100cm depth. Under the same geographical terrain, groundwater level and soil parent material etc., climate change affected the seasonal change of soil salinity. The process of salt accumulation and migration was closely related with environmental factors such as vegetation, soil texture and soil moisture.