Based　on　expatiating　the　rock　blasting　theory　under　multilateral　boundary,　the　thesis　combines　a　project　of　a　high　and　steep　road　cutting　blasting　and　proceeds　application　study　of　deep　hole　control　blasting.　Because　the　calculating　of　charge　quantity　of　a　high　and　steep　road　cutting　blasting　considers　the　various　landform　and　geological　conditions,　the　blasting　result　is　availably　controlled.　Under　the　combined　effect　of　explosion　energy　provided　by　explosive　and　the　latent　positional　energy　in　medium,　the　rock　masse　of　road　cutting　is　adequately　broken　up.　The　flying　rock　does　not　be　seen　and　the　fragmentation　rock　collapses　to　fall　in　the　roadbed　scope.　At　the　same　time,　the　cushion　blasting　technique　is　adopted　nearby　the　road　slope　and　a　complete　road　cut　slope　is　shaped.