Abstract: According to the typical loess in Shuozhou in Shanxi province,tests on its compaction characteristics,shear strength characteristics and disintegration are carried out. The original loess and three improved loess soils are used in the tests. The three loess soils are improved with lime and fly-ash,lime and cement,cement and fly-ash,respectively. The best improved soil plan is brought out.The improve soil is used in the filling engineering of elevator shaft in a pit.The result of numerical simulation indicates that it is feasible to use the improved loess of lime and fly-ash in the engineering project.The test results indicate that the compact hybrid structure is formed by fly ash and loess.The compact hybrid structure is formed by fly ash and loess.The activity of fly ash is activated as a result of the lime mixing.A series of hydration reaction of silicates prompt the intensity of loess and the physical and mechanical properties of improved loess are improved noticeably.