Abstract: It may make the design unsafe when the Technical Code for Building Slope Engineering GB 50330 are directly used in ultra-high slope, especially when the building adjacent to the ultra-high slope, as the design parameters, the resultant and distribution of the lateral pressure are special. Taking a ultra-high slope adjacent to existing tunnel as an example, a method is presented to solve the supporting security which concluded analysis of slope failure modes and problems of use the current code, and the current code and the results of the above analysis are used to design the ultra-high slope supporting, then the deformation law of ultra-high slope and existing tunnel are analysed by use of numerical simulation method. Safety and rationality of the solution method and design idea are validated by monitoring results, which can provide a reference for similar ultra-high slope.