Polyethylene　is　widely　used　in　submarine　DC　cables,　but　polymers　have　the　problem　of　space　charge　accumulation.　Long-term　exposure　to　high　electric　field　will　cause　space　charge　accumulation　in　polymers　which　will　lead　to　severe　problems.　And　the　space　charge　injection　will　be　affected　by　the　pressure　of　the　sea.　Using　the　Piezoelectric　pressure　wave　propagation　method　to　investigate　the　effect　of　pressure　changes　on　space　charge　signal,　the　pressure　will　cause　the　thickness　of　the　sample　to　change,　which　will　cause　the　position　change　of　the　space　charge　signal.　The　experiment　is　designed　to　analysis　the　space　charge　signal　under　high　pressure,　also　correction　is　applied　to　the　signal　according　to　the　change　of　thickness　and　sound　velocity　in　polyethylene.　©　2020　IEEE.