The　increasing　voltage　level　of　HVDC　transmission　requires　the　higher　electrical　performance　of　silicone　rubber　used　in　DC　cable　accessories.　In　order　to　explore　the　excellent　DC　electrical　performance　of　the　composite　silicone　rubber　material,　this　paper　prepared　the　modified　silicone　rubber　filled　with　different　mass　fraction　of　polydopamine　modified　boron　nitride　nanosheets,　and　compared　and　analyzed　the　DC　electrical　performance　of　the　composite　silicone　rubber　under　different　filling　quantities.　The　results　show　that　the　space　charge　accumulation　of　silicone　rubber　can　be　effectively　inhibited　by　the　filling　of　boron　nitride　nanosheets.　The　DC　breakdown　field　strength　of　the　sample　increases　first　and　then　decreases　with　the　increase　of　the　filling　amount,　and　reaches　the　maximum　value　when　the　filling　amount　is　15%,　which　is　23.2%　higher　than　that　of　pure　silicone　rubber.　The　DC　conductivity　decreases　first　and　then　increases,　and　reaches　the　minimum　value　when　the　filling　amount　is　15%.　In　addition,　when　the　filling　amount　is　15%,　the　tensile　strength　of　the　sample　is　increased　by　38.3%　compared　with　that　of　pure　silicone　rubber,　and　the　elongation　at　break　of　the　sample　is　reduced　only　by　2.7%,　basically　maintaining　the　original　elongation　at　break.　The　DC　electrical　and　mechanical　properties　of　boron　nitride　nanosheet　composite　silicone　rubber　modified　with　polydopamine　are　significantly　improved　compared　with　those　without　modification.　The　comprehensive　analysis　shows　that　the　composite　has　better　comprehensive　properties　when　the　filling　amount　is　15%.　©　2024　Science　Press.　All　rights　reserved.