With　the　novel　and　simple　current　distribution　measurement　gasket　developed　by　MPFL,　the　performance　of　a　single　PEM　fuel　cell　with　serpentine　flow　field　was　investigated　without　modifying　any　of　its　components.　Inhomogeneous　current　distributions　were　demonstrated　clearly　by　the　measurement　results.　Current　distribution　at　different　cell　operating　parameters,　including　reactant　gas　flow　rate,　reactant　gas　humidification　temperature　and　cell　operating　temperature,　were　measured　and　the　effects　of　such　parameters　were　analyzed.　Reactant　gas　flow　rate　exert　effects　on　current　distribution　by　influencing　the　reactant　concentration　distribution,　while　the　critical　effects　of　gas　humidification　and　cell　temperature　is　caused　by　their　significant　influence　on　water　balance　and　water　distribution　in　PEM　fuel　cell.　To　fully　understand　the　combined　effects　of　such　factors,　simultaneous　measurement　of　current　distribution,　reactant　distribution,　temperature　distribution　and　humidification　distribution　is　necessary　and　will　be　helpful.