As　a　crucial　part　of　Ultra　High　Voltage　Direct　Current　(UHVDC)　transmission　line,　the　security　of　the　valve　hall　is　stressed　much　importance.　Therefore,　it　is　vital　to　figure　the　insulator　and　shielding　apparatus　properly　and　further　to　obtain　the　applicable　grading　ring　design,　or　corona　discharge　is　possibly　to　take　place,　thus　to　risk　the　safety　of　the　whole　substation.　In　this　paper,　the　model　of　a　new-style　suspension　insulator　in　front　of　the　valve　tower　with　triple　ones　in　cone　conformation　was　established　using　finite-element　method　(FEM)　software　ANSYS.　The　surface　field　distribution　was　calculated　and　was　compared　to　the　critical　field.　In　addition,　several　types　of　optimization　schemes　for　grading　ring　were　put　forward　to　reduce　the　maximum　field.　The　results　indicated　that　the　triple　grading　ring　design　could　help　reduce　the　maximum　field.　©　2018　IEEE.