Abstract：Sensitivity analyses have been considered to be one main method in the solution to identification of many parameters in civil engineering. Based on more than ten examples of deep excavation and slope engineering in loess region，considering the effects of grillage and anchor on the stability of soil slope，the model for internal global safety factor of grillage supporting structure with prestressed anchor in loess region is established by using circular slice and mesh methods. The model for its sensitivity analysis is also established by the global finite-difference method. The relationships among safety factor，design parameters，sensitivity and design parameters are analyzed，from which some valuable results are obtained. The range of preliminary values are given to guide optimum design of grillage supporting structure with prestressed anchor in loess region，which provides some valuable references to the design and construction of this kind of supporting structure. It is proven to be practicable in projects.
