The　audible　noise　radiated　from　the　ac　filter　capacitors　in　HVdc　converter　stations　has　become　a　serious　environment　problem.　The　purpose　of　this　study　is　to　apply　portable　digital　vibrometer　for　in-situ　surface　vibration　measurement　of　capacitors,　to　survey　the　vibration　isolation　and　noise　reduction　effect　of　double-bottom　capacitors　which　are　installed　in　Feng　Xian　Converter　Station　for　the　first　time,　and　to　analyze　the　vibration　and　noise　characteristics　of　ac　filter　capacitors.　Portable　digital　vibrometer　is　a　new　technology　using　eye-safe　visible　laser　and　digital　signal　processing　to　conduct　non-contact　on-line　vibration　velocity　measurement.　The　vibration　of　capacitor　surfaces　and　steel　frames　are　measured　and　amended　according　to　the　measuring　elevation　angle.　On　the　other　hand,　the　noise　at　the　points　arranged　around　the　rail　of　filter　field　is　measured　by　NA28　sound-level　meter　and　1/3　octave　band　real-time　analyzer.　The　data　and　analyses　show　that　the　main　frequency　component　in　vibration　spectrums　of　capacitor　surfaces　and　steel　frames　are　both　100Hz.　And　as　the　double-bottom　design　being　adopted,　the　vibration　at　bottom　surface　decreases　obviously.　Besides,　the　noise　at　the　side　near　the　top　surfaces　of　capacitors　is　much　higher　than　that　at　other　places.