To　obtain　dominant　parameters　of　material　characteristics　for　evaluating　aging　state　of　composite　insulators　effectively,　a　comparative　study　was　performed　on　the　HTV　silicone　rubber　material　aged　by　corona　discharge　in　laboratory　and　by　natural　environment,　in　regard　to　such　parameters　as　hydrophobicity,　surface　leakage　current,　surface　microstructure　and　chemical　composition.　Experimental　results　show　that　the　characteristic　parameters　of　the　silicone　rubber　material　under　two　kinds　of　aging　conditions　exhibit　similar　change　rules.　Corona　aging　condition　decreases　hydrophobicity,　and　increasing　corona　voltage　or　acting　time　leads　to　a　sharper　drop　and　a　slower　recovery　or　even　uncompleted　recovery　in　hydrophobicity.　Hydrophobicity　decline　is　also　observed　in　the　naturally　aged　specimens　from　HC1　level　in　two　years　to　HC5　level　in　15　years.　In　addition,　surface　resistivity　also　decreases　with　aging　time　and　thus　surface　leakage　current　increases.　SEM　and　FTIR　analyses　show　that　both　corona　aging　and　environment　aging　conditions　induce　increasing　surface　defect　density　and　deepening　pits,　and　even　cracks.　Moreover,　aging　gets　the　molecular　chain　of　silicone　rubber　material　broken　and　results　in　the　generation　of　strong　polar　groups,　worsening　the　mechanical　and　insulation　performances　of　the　silicone　rubber.