For optimizing the performance of proton exchange membrane fuel cells (PEMFCs), proper water management in the cell is one of the most important issues because liquid water in PEMFCs have a significant impact on the cell performance. If excessive water accumulate in the cell, including that produced by chemical reactions and the humidification of supplied gases, power generation performance will decrease since the transport of the fuel gas will be blocked by the liquid water that has accumulated in the void of a gas diffusion layer (GDL) or a gas flow channel. On the other hand, the drying of the polymer electrolyte membrane (PEM) causes not only a performance decrement due to an increased proton transport resistance, but also a degradation of membrane. Therefore it is very important to understand the water transport in PEMFCs. Some researchers have investigated the water transport phenomena and mass transfer characteristics in the GDL. Utaka and Koresawa have been proposed a novel GDL (Hybrid type GDL, Fig. 1) which has two different wettability to improve the oxygen diffusivity by controlling the water distributions and movement in the GDL, and have examined the effects of the wettability distribution and PTFE content in the hydrophobic region of the GDL on efficient oxygen diffusivity [1]. Additionally, they also have been proposed a novel gas channel with micro-grooves [2]. The cell performance of PEMFC that combined the hybrid GDL and the gas channel with micro-grooves were experimentally investigated in an attempt to improve the power generation of PEMFC. Figure 2 shows the effects of hybrid GDL and novel gas channel on cell performance, and from this figure, the PEMFC combined the hybrid GDL and gas channel with micro-grooves could enhanced the performance under high current density. A three-dimensional numerical model, which includes the gas channels with micro-grooves, GDLs, catalyst layers in both cathode and anode side and PEM, has been developed to investigate the water transport and power generating characteristics. In addition, we investigate the effectiveness of the hybrid GDL to mitigate liquid water saturation under flooding conditions by using our comprehensive model, and compared with experimental results. Numerical result of liquid water distribution at two different wettability region in GDL shown in Fig. 3. Liquid water distribution biased to hydrophilic regions due to the drawing the water from the hydrophobic region into the hydrophilic region. Furthermore, the performance of PEMFC improved by combined the hybrid GDL and novel gas channel with micro-grooves, and discussed quantitatively. Reference [1] R. Koreaswa and Y. Utaka, J. Power Sources, 271, 16 (2014). [2] Y. Utaka, A. Okabe and Y. Omori, J. Power Sources, 279, 533 (2015). Figure 1