Fuel　cells　are　related　to　a　number　of　scientific　and　engineering　disciplines,　which　include　electrochemistry,　catalysis,　membrane　science　and　engineering,　heat　and　mass　transfer,　thermodynamics　and　so　on.　Several　thermophysical　phenomena　such　as　heat　transfer,　multicomponent　transport　and　two　phase　flow　play　significant　roles　in　hydrogen　proton　exchange　membrane　fuel　cells　and　direct　methanol　fuel　cells　based　on　solid　polymer　electrolyte　membrane.　Some　coupled　thermophysical　issues　are　bottleneck　in　process　of　scale-up　of　direct　methanol　fuel　cells　and　hydrogen　proton　exchange　membrane　fuel　cells.　In　present　paper,　experimental　results　of　visualization　of　condensed　water　in　fuel　cell　cathode　microchannels　are　presented.　The　equivalent　diameter　of　the　rectangular　channel　is　0.8mm.　Water　droplets　from　the　order　of　0.08mm　to　0.8mm　were　observed　from　several　different　locations　in　the　channels.　Several　important　problems,　such　as　generation　and　change　characteristics　of　water　droplet　and　gas　bubble,　two　phase　flow　under　chemical　reaction　conditions,　mass　transfer　enhancement　of　oxygen　in　the　cathode　porous　media　layer,　heat　transfer　enhancement　and　high　efficiency　cooling　system　of　proton　exchange　membrane　fuel　cells　stack,　etc.,　are　discussed.