Seawater　hydraulic　axial　piston　pumps　are　widely　used　in　underwater　apparatus　systems　in　recent　years.　Reliability　of　the　valve-port　plate　pair　is　vital　to　the　performance　of　seawater　hydraulic　axial　piston　pumps.　As　the　distribution　information　of　the　material　combinations　and　working　conditions　of　seawater　hydraulic　axial　piston　pumps　are　insufficient,　the　probability　reliability　analysis　methods　are　not　available　for　the　valve-port　plate　pair.　This　paper　develops　a　non-probabilistic　reliability　convex　model　for　the　valve-port　plate　pair.　Firstly,　the　rotation　of　the　pump　cylinder　is　partitioned　into　six　stages.　Based　on　this　partition,　the　dynamic　models　of　contact　pressure　and　pv　value　(the　product　of　contact　specific　pressure　and　linear　velocity)　of　the　valve-port　plate　pair　are　derived　by　accounting　for　the　pre-compression　angle.　Secondly,　the　marginal　interval　for　the　limiting　[pv]　value　(It　is　the　usual　criterion　to　evaluate　the　critical　operating　conditions　under　which　the　material　fails)　of　the　material　combination　was　obtained　through　adhesive　wear　tests.　Thirdly,　a　limit-state　function　is　then　established　based　on　the　stress-strength　interference　model.　Finally,　the　analysis　and　sea　test　results　indicate　that　the　reliability　of　the　valve-port　plate　pair　has　significantly　improved　by　adding　auxiliary　support　on　the　port　plate.