With　the　increasing　integration　of　seawater　hydraulic　components,　much　attention　has　been　paid　to　the　tribological　characteristics　of　PEEK　bidirectional　sliding　against　AISI630　tribopair.　In　the　study,　a　bidirectional　wear　model　based　on　Inverse　Gaussian　(IG)　process　is　proposed　based　on　bidirectional　wear　experiment.　Impact　wear　occurs　when　the　tribopair　changes　the　motion　direction.　Through　analysing　the　wear　process　and　worn　surface　morphology　of　PEEK　against　AISI630　tribopairs,　it　is　found　that　the　impact　wear　would　accelerate　the　formation　and　uniform　distribution　of　PEEK　transfer　film,　and　the　increase　of　reversal　frequency　can　improve　the　tribological　characteristics　of　the　bidirectional　tribopairs.　The　IG　model　considering　the　reversal　impact　can　accurately　illustrate　the　performance　degradation　path　of　actual　impact　wear.