Bipolar plate of stack in polymer electrolyte membrane fuel cell (PEMFC) has high cost and heavy weight. In this study, low carbon steel was used as a base metal of bipolar plate for the lower cost than stainless steels, which are widely researched as bipolar plate. Low carbon steel has not a good corrosion resistance. In order to improve the corrosion resistance and electrolytic conductivity, low carbon Steel needs to be surface modified. We made chromium electroplated layer of 5㎛ and 10㎛ thickness on the surface of low carbon steel, and it was thermally nitrided for 3hours at 1173K in a furnace with 50torr nitrogen gas pressure. Cross-section and surface microstructures of surface treated low carbon steel were investigated using OM and SEM. Also crystal structures are observed by XRD. Interfacial contact resistance and corrosion test were considered to simulate the internal operating conditions of PEMFC stack. The corrosion test was performed in 0.1N H2SO4 + 2ppm F- solution at 80°C. The results show that the surface modified steel plates have good corrosion resistance and relatively low interfacial contact resistance, and it should be candidate material as a bipolar plate of PEMFC.