Blocked　flow　channel　can　enhance　the　reactants　transfer　process　and　improve　the　output　performance　of　proton　exchange　membrane　fuel　cells.　In　waved-like　blocked　flow　channels,　the　flow　resistance　at　the　windward　side　can　be　reduced　because　of　the　streamline　shape　design.　However,　the　vortexes,　which　account　for　the　power　loss,　can　be　formed　at　the　leeward　sides.　In　this　work,　a　two-dimensional,　two-phase,　non-isotherinal　and　steady　state　model　is　developed,　and　flow　channels　with　different　wave-like　blocks　are　designed　to　investigate　the　effects　of　windward　sides　and　leeward　side　on　output　performance　of　proton　exchange　membrane　fuel　cells.　Simulation　results　show　that:　when　the　heights　and　weights　of　wave-like　blocks　are　both　fixed,　longer　leeward　side　of　blocks　facilitate　to　reduce　the　vortexes　forming　and　decrease　the　pumping　powers,　in　the　meantime,　the　net　powers　and　the　efficiency　are　improved.　However,　when　the　leeward　sides　of　blocks　are　shortened　and　windward　sides　are　lengthened,　vortexes　forming　in　flow　channels　are　strengthened　and　pumping　powers　are　improved,　and　the　net　powers　are　reduced.　Moreover,　when　the　leeward　side　is　prolonged,　the　liquid　water　in　flow　channels　can　be　removed　more　easily.