At　present,　the　blasting　theory　of　high　and　steep　rock　slope　mainly　focuses　on　flat　terrain,　ignoring　the　influence　of　micro-terrain　boundary　factors　on　blasting　effect,　which　leads　to　excessive　blasting　energy　and　affects　the　stability　of　slope.　Therefore,　based　on　the　theory　of　multilateral　boundary　rock　blasting,　this　paper　deduces　the　calculation　formula　of　blasting　charge　for　high　and　steep　rock　slope　under　multilateral　boundary　conditions,　and　verifies　it　with　field　test.　The　results　show　that:　(1)　The　multilateral　boundary　charge　calculation　formula　directly　includes　micro-topography　boundary　conditions　and　blasting　effect,　and　the　rock　blasting　theory　is　based　on　the　interaction　of　blasting　energy　provided　by　explosives　and　potential　energy　in　medium,　which　effectively　improves　the　energy　utilization　rate　of　explosives.　(2)　The　influence　of　surplus　blasting　energy　on　the　surrounding　environment　under　different　boundary　conditions　is　controlled,　and　the　explosive　explosion　effect　is　effectively　controlled,　so　that　a　stable　high　and　steep　slope　of　open　pit　mine　is　formed　after　blasting.