In this study, novel flow channel which has a tapered depth from inlet to outlet is suggested to improve the performance of polymer electrolyte membrane fuel cell (PEMFC) by reducing concentration losses at high current density area. We designed three types of inclined channel which have the same inlet depth but different outlet depth. Then, the characteristics of performance of PEMFC were investigated with different types of channel shape. The performance of PEMFC was evaluated at temperature of 60 degree Celsius. As we compared polarization curves and power density curves, we could verify that PEMFCs with inclined channel showed better performance than that with conventional channel. Moreover, electrochemical impedance spectroscopy (EIS) was also used to figure out the factors that make fuel cell performance improved. Furthermore, a numerical analysis was conducted to investigate the effect of inclined channel on the performance of PEMFC from the perspective of oxygen depletion and flooding.