Different　discharge　phenomena　show　on　insulator　surfaces　of　different　states,　so　here　according　to　their　surface　discharge　intensity,　we　divide　these　surface　discharges　into　three　types,　namely　weak　discharge,　interstitial　arc　discharge　and　continuous　arc　discharge.　After　conducting　a　number　of　tests,　we　statistically　summarized　and　analyzed　the　harmonic　features　and　the　phase　angle　features　of　leakage　current　in　different　discharge　types,　revealed　the　relation　between　them,　and　investigated　the　effect　of　different　pollution　and　hydrophobicity　of　composite　insulator　on　surface　discharge　type.　The　results　indicate　that　the　types　and　features　of　discharges　on　insulator　surfaces　of　different　states　can　be　obtained　through　analyzing　the　harmonic　features　and　the　phase　angle　features　of　leakage　current.　When　the　surface　hydrophobicity　of　a　composite　insulator　gets　worse,　the　weak　discharge　reduces　slightly　in　proportion,　the　interstitial　arc　discharge　partly　transforms　into　continuous　arc　discharge,　and　the　continuous　arc　discharge　increases　in　proportion.　When　the　surface　pollution　of　a　composite　insulator　gets　heavier,　the　weak　discharge　partly　transforms　into　interstitial　arc　discharge　and　continuous　arc　discharge,　and　both　the　interstitial　arc　discharge　and　the　continuous　arc　discharge　increase　in　proportion.　In　another　word,　the　characteristics　of　leakage　current　also　reflect　the　surface　states　of　composite　insulators.