The　PD　diagnosis　of　three-phase　cross-bonded　cable　is　affected　by　environment　and　mutual　crosstalk.　In　order　to　solve　the　problem,　this　paper　introduces　the　PD　detection　and　identification　for　cross-bonded　cable　based　on　vector　analysis　method.　The　principle　of　method　is　that　different　PD　pulse　has　different　attenuation　characteristic.　The　three-phase　amplitude　relation　diagram　(3PARD)　is　established　based　on　the　amplitude　relation　of　three-phase　pulse.　The　diagram　is　used　to　distinguish　external　noise　from　internal　PD　signal　and　separate　different　PD　sources.　It　can　be　concluded　from　the　result　of　theoretical　research　and　on-site　test　that　the　method　has　better　feasibility　and　superiority　in　PD　diagnosis　for　HV　cross-bonded　cable　and　can　be　effectively　applied　to　the　on-site　detection　and　insulation　diagnosis.