The　key　factor　that　limits　the　output　performance　and　commercial　applications　of　air-cooled　proton　exchange　membrane　fuel　cell　(PEMFC)　is　how　to　maintain　the　balance　between　heat　dissipation　and　water　retention.　In　order　to　tackle　this　issue,　new　cathode　flow　field　with　metal　foam　is　experimentally　investigated　due　to　superior　heat　dissipation　and　water　retention　capability　of　metal　foam.　Experimental　results　demonstrated　that　when　the　height　of　metal　foam　is　1　mm　and　the　width　of　metal　foam　increases　from　1　mm　(case　2)　to　5　mm　(case　6),　the　temperature　of　air-cooled　PEMFC　decreases　by　8.4　degrees　C　under　current　of　15　A　due　to　the　synergic　enhancement　of　heat　dissipation　and　electrochemical　performance,　indicating　the　thermal　management　improvement　of　aircooled　PEMFC.　As　the　metal　foam　height　increases,　however,　the　thermal　management　performance　of　aircooled　PEMFC　first　increases　and　then　decreases.　Therefore,　case　6　is　considered　to　be　the　optimal　sample　under　the　constraints　of　the　thermal　management　performance　and　compactness　of　air-cooled　PEMFC.　By　comparing　with　conventional　parallel　flow　fields　with　the　widths　of　1　mm,　3　mm　and　5　mm　(case　1,　case　3　and　case　5),　the　net　output　performance　of　case　6　increases　by　3.4　%,　8.8　%　and　55.1　%　and　the　compression　work　of　case　6　decreases　by　69.7　%,　38.3　%　and　64.4　%　under　the　same　temperature　(50　degrees　C)　and　current　(15　A),　which　means　higher　practical　application　potential　and　lower　parasitic　power　requirement.