In recent years, fuel cells that are capable of converting chemical energy to electrical energy by using an electrochemical reaction are widely studied. Polymer fuel cells have many advantages, including low weight, high efficiency and low operating temperature. One of the obstacles to the widespread use of polymer fuel cells is the cost of their construction, which is effectively dependent on the cost of producing bipolar plates. Recently, use of metallic bipolar plates is the preferred choice for bipolar plates because of its properties such as good strength, chemical stability, high electrical conductivity and high thermal conductivity. Among the various metals, the 316L stainless steel is more concerned, but with a large barrier reducing the efficiency of bipolar plates made of stainless steel, they are susceptible to corrosion in a wet and acidic environment of the fuel cell; therefore, some surface modification methods or applying protective coatings to improve corrosion resistance are essential. In this study, the Ti/TiN nanmetric multilayer coating is used to improve the surface properties and the electrochemical corrosion resistance of 316L austenitic steel bipolar plates. Multi-layer coating is indicated by cathodic arc physical vapor deposition process. The electrochemical properties of coated and uncoated steel in a polymer fuel cell simulation environment were carried out by potentiostatic polarization and potentiodynamic polarization experiments at ambient temperature and 70 °C. The results of potentiodynamic polarization results show that the Ti/TiN nanometric multi-layer coating increases the polarization of uncoated steel by about 25 times at ambient temperature and 1000 times at 70 ° C. The contact resistance of the interface is about 12.5 m?.cm2 before potentiostatic polarization test.This amount of contact resistance is clearly less than the uncoated substrate. The contact resistance remains almost unchanged after a potentiostatic polarization test for 1 hour. In addition, the high wettability angle (95) for coating, indicates hydrophobic properties that can improve the management of water inside the fuel cell stack. Keywords: Fuel Cell, Bipolar Plates, Contact Resistance,Cathodic Arc Physical Vapor Deposition,Impedance Spectroscopy.