Soil samples were taken from Kelamayi to Elm Ditch along provincial road No.201 in Xinjiang Wei Autonomous Region and the main factors influencing the expansion characteristics of carbonate saline soil were studied through laboratory test.The effects of the natural vertical distribution of saline soil layers on the expansion of saline soil were discussed at first.The expansion ratio was found to vary with soil sampling depth and the expansion was most significant between 25 and 75 cm below soil surface.By taking seasonal variation and temperature variation into consideration,the characteristics of saline soil in freeze-thaw cycle studied and temperature was found to have little effect on the expansion characteristics of carbonate saline soil.Expansion test was made with specimens containing salt 0.5%,1.0%,1.5%,and 2.0% in weight to analyze how salt content affects the expansion characteristics of the soil.Results show that the maximum expansion ratio increased from 10.0% to 22.5% as salt content increased from 0.5% to 2.0%.