To　explore　the　deformation　patterns　and　failure　mechanism　of　rock　slopes　with　fault　fracture　zone　induced　by　over-excavation,　an　excavation　slope　project　in　Wudang　District,　Guizhou　Province　was　taken　as　an　example.　The　finite　difference　method　software　FLAC3D　was　utilized　to　analyze　key　indicators　such　as　displacement,　stress,　safety　factor,　and　maximum　shear　strain　increment.　Research　indicates　slope　displacement　increases　with　excavation.　The　gradual　exposure　of　fault　fracture　zone　alters　the　distribution　of　displacement　along　the　slope＇s　free　surface　direction,　amplifying　the　deformation　of　the　rock　layers　on　the　slope　surface.　The　stress　field　formed　by　excavation　is　unfavorable　to　slope　stability.　In　the　vicinity　of　fault　fracture　zones,　stress　release　is　intense,　manifesting　as　tensile　stress,　with　its　range　gradually　expanding　as　excavation　progresses.　The　peak　of　maximum　shear　strain　increment　primarily　exists　at　the　foot　of　the　slope.　The　exposure　of　the　fault　fracture　zone　promotes　the　shear　strain　increments　development,　forming　a　continuous　sliding　surface　during　over-excavation　stage,　resulting　in　arc-shaped　shear　failure　along　the　fault　fracture　zone　from　the　slope　foot,　which　is　similar　to　actual　failure　conditions.　The　slope　safety　factor　decreases　with　the　progress　of　excavation.　The　exposure　of　fault　fracture　zone　accelerated　the　rate　of　decline　in　slope　safety　factor,　changing　from　a　modest　1.9%　to　a　critical　11.8%.　During　the　over-excavation　stage,　the　slope　instability　was　further　exacerbated,　with　the　slope　safety　factor　dropping　from　1.12　to　0.95,　a　decrease　of　15.2%,　and　the　slope　transitioning　from　a　condition　of　basic　stability　to　instability.　The　slope＇s　entire　deformation　and　failure　process　can　be　summarized　as　＂unloading　deformation　-　tensile　deformation　-　compression　bending　deformation　-　shear　failure＂.　The　research　results　can　provide　theoretical　support　and　guidance　for　stability　analysis,　quantitative　excavation　design,　and　early　warning　systems　for　such　slopes　in　engineering　construction.