In this study, three-dimensional, non-isothermal, and unsteady numerical model considering liquid water in gas channel and GDL have been developed to investigate effect of water transport on cell performance. In addition, a novel gas channel with micro grooves is improved the liquid water discharge from GDL to gas channel, and have a high limiting current density. Thus, the effect of liquid water in the flow channel with micro grooves on the unsteady responses of PEFCs membrane resistance was discussed. As a result, accumulated liquid water in the flow channel has a significant influence on time responses of membrane resistance to prevent the gas transport.