The　complex　surface　building　method　of　the　existing　screw-sleeve　pair　goes　against　the　moulding　process.　According　to　the　problem,　a　surface　building　method　of　the　pair　based　on　circular　cross　section　and　cylindrical　helix　was　investigated,　the　surface　equation　of　cone　screw　and　sleeve　was　established　based　on　the　space　meshing　theory.　The　contact　characteristics　and　the　sealing　mechanism　of　the　pair　were　systemmatically　studied.　The　theory　without　axial　motion　during　the　movement　of　the　screw-sleeve　pair　was　verified　by　motion　simulation.　Analysis　show　that　the　new　surface　building　method　makes　the　mathematical　modeling　easier,　which　is　favorable　to　numerical　calculation　and　moulding　process.　With　good　contact　characteristics　and　sealing　performance,　the　screw-sleeve　pair　built　by　this　method　will　meet　the　working　condition　of　the　cavity　type　seawater　hydraulic　pump.　©,　2015,　Beijing　University　of　Technology.　All　right　reserved.