In　this　paper,　the　key　friction　pairs　(slipper/　swashplate　pair,　valve/port　plate　pair　and　sliding　bearing/shaft　pair)　of　the　seawater　piston　pump　are　equivalent　to　stiffness　and　damping,　and　the　relevant　expressions　are　obtained.　On　this　basis,　the　influence　of　working　pressure　on　the　equivalent　stiffness　and　damping　coefficient　is　studied.　The　results　show　that　the　equivalent　stiffness　of　the　slipper/swashplate　pair　and　the　valve/port　plate　pair　increases　with　the　increase　of　the　working　pressure.　Whereas,　the　equivalent　damping　of　the　slipper/swashplate　pair　and　the　valve/port　plate　pair　decreases　with　the　increase　of　the　working　pressure.　In　addition,　the　equivalent　stiffness　and　damping　coefficient　of　the　sliding　bearing/shaft　pair　increases　with　the　working　pressure　increases.　However,　the　amplitude　of　the　equivalent　stiffness　and　damping　coefficient　of　the　slipper/swashplate　pair　and　the　valve/port　plate　pair　does　not　change　much　with　the　working　pressure.　Comparatively,　the　amplitude　of　the　equivalent　stiffness　damping　coefficient　of　the　sliding　bearing　varies　greatly　with　the　working　pressure.　©　2019　IEEE.