Temperature　stability　is　one　of　the　most　determinant　factor　in　the　design　of　HVDC　cable　insulation,　since　the　conductivity　and　correlated　field　strength　distribution　are　temperature-dependent.　Low　density　polyethylene　(LDPE)-based　cross-linked　polyethylene　(XLPE)　material　is　the　prevailing　material　system　in　HVDC　cable　insulation.　Here,　we　report　a　method　on　improving　the　temperature　stability　for　the　DC　performance　of　XLPE　by　changing　the　starting　material　into　linear　low　density　polyethylene　(LLDPE).　In　order　to　understand　the　role　of　crosslinking　agent-dicumyl　peroxide　(DCP),　we　investigate　DC　breakdown　characteristics　of　LLDPE-based　materials　with　different　crosslinking　degrees　under　different　temperatures.　The　results　show　that　DC　breakdown　strength　for　LLDPE-based　materials　varies　smaller　compared　with　LDPE-based　materials.　Further　differential　Scanning　Calorimetry　(DSC)　results　suggest　that　the　temperature-stable　DC　performance　for　LLDPE　material　stems　from　its　higher　crystallinity　as　well　as　melting　point　than　LDPE　samples.　And　the　optimal　DCP　content　for　LLDPE-based　materials　has　been　further　discussed.　©　2018　IEEE.