With　the　development　of　the　power　system,　composite　post　insulators　are　widely　used　in　China.　However,　the　contamination　flashover　of　post　insulators　caused　by　the　loss　of　the　hydrophobicity　of　silicone　rubber　remains　a　threat　to　the　grid,　especially　in　EHV　and　UHV　substation.　The　statue　variations　of　the　composite　post　insulator　surface　are　studied　in　this　paper.　Based　on　the　cluster　analysis　method,　the　characteristics　of　the　leakage　current　was　also　investigated,　and　a　continuous　Hopfield　neural　network　threshold　optimization　model　is　constructed　to　select　the　class-space　distance　threshold.　Sixteen　parameters　are　extracted　to　characterize　the　surface　state　of　the　composite　post　insulator.　The　discharge　model　spectrum　diagram　of　composite　post　insulator　surface　is　also　established,　aiming　for　the　diagnosis　of　the　degree　of　hydrophobicity　loss　and　salt　deposit　density　over　the　insulator　surface.　The　results　show　that　when　the　hydrophobic　performance　is　deteriorated,　the　proportion　of　weak　discharges　is　slightly　reduced,　and　the　intermittent　arc　discharges　are　partially　converted　into　continuous　arc　discharges.　Besides,　when　the　pollution　degree　is　increased,　the　weak　arcs　were　partially　converted　into　intermittent　arc　discharges,　and　the　proportion　of　intermittent　arc　discharge　increased.　Therefore,　it　is　indicated　that　these　parameters　could　be　used　to　recognize　the　degree　of　hydrophobicity　loss　over　the　surface　of　the　composite　post　insulator.　This　work　can　enrich　the　recognition　methods　of　surface　statue　of　composite　post　insulators　and　may　provide　useful　reference　for　performance　evaluation　of　composite　post　insulators　in　service.　©　2020　IEEE.