Dynamic　characteristics　are　important　information　in　analyzing　and　understanding　PEM　fuel　cell　performances　and　detailed　local　dynamic　information　is　extremely　important　in　the　understanding　of　fundamental　mechanisms.　in　this　study,　the　input　parameters　studied　include　humidification　temperature　of　the　reactant　gases,　operating　temperature,　and　operating　backpressure　and　the　local　dynamic　responses　are　the　local　current　densities.　The　fuel　cell　used　is　a　PEM　fuel　cell　with　a　single　channel　serpentine　flow　field　and　the　local　current　densities　are　directly　measured　using　the　current　density　distribution　measurement　gasket　and　a　multi-channel　potentiostat.　The　experimental　results　show　that　very　different　local　dynamic　responses　exist　even　though　the　response　of　the　average　current　shows　very　little　dynamics.　Especially　when　the　humidification　temperature　increases　from　a　low　value　to　moderate　value,　the　responses　of　the　local　current　density　in　the　upstream　are　very　different　from　those　in　the　downstream.　(C)　2009　International　Association　for　Hydrogen　Energy.　Published　by　Elsevier　Ltd.　All　rights　reserved.