Abstarct: Abstaract Fuel cells have drawn incredible attention as a promising candidate for the power generation technology, particularly in the last decades. The promise of high energy efficiencies and near-zero pollution, make fuel cell an ideal nominee for power generation in transportation systems. In Polymer Electrolyte Membrane Fuel Cell (PEMFC), heat and water are generated as a side-production. The accumulated water leads to a decrease in PEMFCs efficiency; therefore, water has to be removed and flooding has to be prevented. In this study, by an experimental model and implementation of transparent Gas-Diffusion laxyer (GDL), water transport in PEMFC is visualized and the fingering mechanisms in GDL are studied. and Effect of added Micro Porous laxyer (MPL) on water flooding in GDL has been also examined. Results show the characteristics of the two-phase regime in GDL are similar to the capillary fingering. Moreover; the fingers inside the GDL are generated by the capillary forces. In addition, it is observed that lateral flow on the Catalyst laxyer (CL) leads to an increase in water flooding in GDL in which PEMFC efficiency is decreased. The our observations show that by inserting MPL, lateral flow on CL terminated and the fingers at preferential location on MPL surface in GDL appear and grow. The fingers also select direct pathes to approach gas channel. In this way, it leads to descend in water flooding and reform of PEM efficiency.