Taking the saline soil in Lacustrine plain of Lop Nor as the research object, the paper carried out experiment on impact of different factors on salt expansion such as times of freeze-thaw cycle, dry density and water content. The results showed that when the water content of saline soil is 10% and 13%, the salt expansion increment appears peak value in the third cycle;and when the water content of saline soil is 16%, the increment peak of salt expansion appears in the sixth time of freeze-thaw cycle.When the sample in different water contents and dry densities are effected by many times of freeze-thaw cycle, the salt expansion force shows the increase trend with the increase of times of freeze-thaw cycle.Under condition of the same dry density, the salt expansion force reaches the peak value when the water content of sample is the optimal water content.When the water content of saline soil is less than the optimal water content, the salt expansion force increases with the increase of water content;when the water content is larger than the optimal water content; the salt expansion force reduces with the increase of water content.