Abstract: The salt migration characteristics of silt loam soil column were analyzed under the process of leaching by the rainstorm in different groundwater depths under cotton vegetation．The results show that the salinity of 0～30cm soil layer migrates down to 30～105cm when the depth to groundwater is 1．5 m which belongs to shallow desalt，and moves up to topsoil easily again；the salinity of 0～83cm soil layer migrates down to 83～200cm when the depth to groundwater is 2．5m which belongs to central desalt；the salinity of 100～200cm soil layer migrates down to 205～255cm when depth to groundwater is 3m which belongs to deep dealt.