Without　pump　to　supply　fuel,　methanol　solution　is　delivered　by　gravity,　capillarity　and　natural　convection　to　membrane　electrode　assembly　where　proceeding　electrochemical　reaction　in　passive　direct　methanol　fuel　cell　(DMFC).　Slow　methanol　diffusion　rate　and　oxygen　diffusion　rate　may　cause　fuel　cell　performance　degradation.　In　this　paper,　a　three-dimensional,　two-phase,　transient　anode　model　of　passive　DMFC　is　developed.　Mass　transfer　condition　of　methanol　solution　and　carbon　dioxide　gas　in　the　anode　is　analyzed.　The　results　indicate　removal　of　CO2　in　the　DMFC　anode　is　significant　affected　by　collector　plate　structure.