This　analysis　is　based　on　a　highway　project　in　Guangdong　province,　involving　a　tall,　steep,　and　rock-excavating　slope　with　cataclastic　structures.　Quantitative　analysis　of　the　stress-strain　trend,　possible　failure　models　and　safety　factors　during　the　slope　excavation　were　investigated　by　the　discrete　element　program　UDEC.　The　following　results　were　obtained:　(1)　The　slope　with　joint　fissure　developed　was　in　anticlinal　core　and　the　stability　was　greatly　influenced　by　the　extroversion　of　rock　level.　(2)　The　primitive　balance　of　the　slope　was　broken　during　the　excavation,　which　induced　large　range　shear　failure　zone　in　the　internal　part　of　the　slope,　and　the　whole　circle-broken　similar　to　soil　slope　appeared.　(3)　The　excavation　slope　was　in　a　critically　stable　state,　but　wide　area　landslide　could　be　induced　by　certain　triggering　factors.　Based　on　these　results,　a　comprehensive　treatment　scheme　was　adopted　and　implemented　through　the　methods,　such　as　reinforcing　the　broken　rock　with　concrete　lattice　beam-anchor　(cable);　minimizing　erosion　and　preserving　the　slope　strength　with　an　efficient　drainage　system;　and　protecting　the　slope　with　grouted　rubble.　The　integrity　of　the　high　standard　highway　was　maintained　and　the　slope　was　reinforced　during　time　the　plan　was　carried　out.　©　2009　ASCE.