Abstract: Based on the investigation of distribution of the loess-like saline soil foundations in Xining, engineering characteristics and the damages to the building, respectively, from three characteristics of the settlement by soaking, salt expansion and causticity of the loess-like saline soil, the author research into the effects on the nature of the foundations from the changes of salinity in the backfill in the loess-like saline soil foundations in Xining. Some of the points raised by the practice has achieved a certain degree of social effects and economic benefits.