Liquid-phase　plasma　is　widely　used　in　industry,　so　it　is　important　to　study　its　characteristics.　In　this　paper,　an　experimental　system　utilizing　a　cylindrical　pressure　tank　with　adjustable　hydrostatic　pressure　for　studying　liquid-phase　pulsed　discharge　plasma　is　designed,　and　the　components　and　experimental　principles　of　the　system　are　introduced　in　detail.　Based　on　this　experimental　system,　the　influence　of　hydrostatic　pressure　on　the　characteristics　of　liquid-phase　plasma　was　investigated　under　varying　voltage　levels　and　electrode　spacings.　The　results　demonstrate　that　the　experimental　system　can　effectively　generate　and　observe　liquid-phase　plasma.　As　hydrostatic　pressure　increases,　the　pre-breakdown　delay　at　15　kV　and　a　2　mm　electrode　gap　increases　from　25.6　mu　s　at　0.1　MPa　to　447.2　mu　s　at　0.5　MPa,　while　the　duration　of　the　main　discharge　stage　decreases　from　224.4　to　210.4　mu　s.　At　13　kV　with　a　2　mm　electrode　gap,　the　emission　spectrum　intensity　and　the　electron　density　of　the　discharge　plasma　decrease　with　increasing　hydrostatic　pressure.　The　electron　temperature　in　the　plasma　channel　ranges　from　11,000　K　to　16,500　K.　In　addition,　the　discharge　process　phenomena　were　analyzed　using　typical　high-speed　camera　images,　highlighting　the　characteristics　of　the　discharge　plasma　at　each　stage.　Finally,　the　shortcomings　and　improvement　of　the　experimental　system　are　analyzed.