Abstract: In recent years, coarse particle saline soil as a kind of special soils is often encountered in engineering construction in northwest China. In order to grasp the special engineering properties of the soil mass, this study selects 28 test points and 576 pieces samples of 4 test sites in northeastern Xinjiang and Hexi regions of Gansu Province to collapsible testing research. The test results show that the foundation soil can cause salt resolving slump when the easy resolving salt content exceeds 0.5％ ～1％ and the permeability coefficient no less than 10-7. At the same time, the test results show that soil's periodic expansion and contraction phenomenon are more dangerous than single salt expansion and salt resolving slump.