The　viaduct　No.II　of　Shikongshan　in　Zhangzhou-Longyan　expressway　goes　through　a　high　slope　area　with　complicated　engineering　geological　condition.　There　are　three　sets　of　dominant　structural　planes　J1,　J2,　J3　developed　in　the　high　slope　rock　masses.　The　slope　surfaces　combined　with　single　dominant　structural　plane　of　rock　masses,　two　sets　of　dominant　structural　planes　and　three　sets　of　dominant　structural　planes,　are　analyzed　by　stereographic　projection,　respectively.　The　result　shows　that　the　natural　slope　is　basically　stable.　Furthermore,　the　stability　of　slope　to　be　excavated　and　natural　slope　is　evaluated　by　Sarma　limit　equilibrium　method,　and　the　calculation　results　show　that　the　high　slope　is　integrally　stable.