A　hydraulically　actuated　sampling　valve　is　developed　for　the　sub-sea　situ　pore-water　and　bottom　seawater　sampler.　A　unique　pressure　compensation　design　for　the　valve　core　is　adopted　in　the　sampling　valve,　which　makes　the　sampling　valve　open　or　closure　reliably　under　high　pressure.　Based　on　the　developed　sampling　valve,　a　fluid　sampler　is　manufactured,　which　includes　three　collecting　bottles,　one　equilibrium　bottle,　one　negative　pressure　bottle,　one　sampling　valve,　and　a　set　of　control　unit.　The　simulation　model　of　the　developed　sampler　is　established　for　the　whole　sampling　process　using　the　AMESim,　and　the　dynamic　and　static　characteristics　of　the　sampling　valve,　check　valve　in　the　collecting　bottle,　negative　pressure　bottle　are　obtained　numerically.　And　then,　the　simulation　tests　of　the　sampling　valve　are　conducted　at　the　simulated　high　pressure　tank　of　45　MPa.　The　developed　sampling　valve　and　sampler　have　been　applied　on　the　sub-sea　situ　pore-water　and　bottom　seawater　sampling　system　and　tested　at　the　situ　pore-water　and　bottom　seawater,　which　could　also　be　widely　used　in　marine　and　offshore　oil　and　gas　environmental　investigation.　This　research　will　lay　the　foundation　for　the　development　of　undersea　tools　for　nature　gas　hydrate　survey.