Water　hydraulic　axial　piston　motor　(WHAPM)　is　one　of　the　key　components　in　water　hydraulic　system.　It　is　essential　to　identify　the　desired　engineering　materials　and　material　combinations　for　improving　the　WHAPM,　which　are　featured　by　strong　wear　and　erosion　resistance.　As　the　candidate　materials　of　friction　pairs　in　WHAPM,　the　tribological　characteristics　of　30　wt%　carbon　fiber-reinforced　PEEK　(PEEK+CA30)　sliding　against　17-4PH　precipitation-hardening　stainless　steel　under　fresh　water　lubrication　were　investigated.　The　friction　experiments　were　conducted　on　MCF-10　ring-on-ring　test　rig.　With　the　help　of　metallographic　microscope,　an　attempt　was　made　to　approach　the　tribological　properties　of　friction　pair.　The　experimental　results　showed　that　the　ideal　sliding　velocity　is　also　about　1　m/s　when　the　applied　load　is　between　200　and　600　N.　It　can　be　concluded　that　the　slipper　designed　based　on　the　principle　of　residual　pressure　coefficient　bearing　with　auxiliary　supporting　area　is　an　effective　way　to　decrease　the　actual　pv　value　in　the　prototype　of　WHAPM.　The　research　outcomes　will　lay　the　foundation　for　the　design　of　key　friction　pairs　in　the　water　hydraulic　components　and　system.